Provisioning instant communications for a community of users

1. A computer-implemented method for provisioning instant communication services comprising:

facilitating, by a first domain, instant communications for a first online community having a first set of members, the first online community operating from a second domain different from the first domain;

generating an instant communication session associated with a first web page accessed by a first member of the first online community, the first web page from a website of the first online community;

causing a first user interface to be displayed as an overlay on the first web page, the overlay covering a portion of the first web page, wherein the first user interface includes a chat window enabling the first member to exchange messages with a second member from the first set of members of the first online community and a list window displaying at least one member from the first set of members, the list window adjacent to the chat window;

responsive to a second web page being accessed by the first member, retrieving session state information associated with the instant communication session and the messages exchanged between the first member and the second member, the second web page from the website of the first online community;

preserving, based on the session state information, the instant communication session from the first web page to the second web page by causing the same first user interface, including the chat window and the adjacent list window, to be overlaid on the second web page, the session state information describing a status of the instant communication session and including information describing one or more messages sent by the first member, the second web page accessed by the first member and from the website of the first online community;

wherein the facilitating enables the first member of the first online community to exchange one or more messages with the second member of the first online community using an instant communication technology;

facilitating, by the first domain, instant communications for a second online community having a second set of members, the second online community operating from a third domain different from the first and second domains; wherein the first user is a member of the first online community and the second online community, the user having a first list of friends for the first online community and a second list of friends for the second online community; and

causing an aggregated list of friends to be displayed on the first web page accessed by the user from the website of the first online community, the aggregated list of friends comprising one or more friends in the first list of friends and one or more friends in the second list of friends.

2. The method of claim 1 wherein the instant communication technology uses instant messaging (IM).

3. The method of claim 1 further comprising:

storing, at a system in the first domain, the session state information for the first member, the session state information comprising information related to the first user interface.

4. The method of claim 1 wherein causing the first user interface to be displayed as the overlay on the first web page comprises:

for at least one member of the first online community:

displaying presence information for the member; and

displaying status information for the member.

5. The method of claim 1 wherein causing the first user interface to be displayed as the overlay on the first web page comprises:

displaying a notification sent to the first member from the second member of the first online community.

6. The method of claim 1 wherein the facilitating comprises:

providing a first set of application programming interfaces (APIs) for the first domain, the first set of APIs being callable from the second domain for exchanging information with the first domain; and

providing a second set of application programming interfaces (APIs) for the second domain, the second set of APIs being callable from the first domain for exchanging information with the second domain.

7. The method of claim 1

wherein the facilitating enables a third member of the second online community to exchange one or more messages with a fourth member of the second online community using the instant communication technology.

8. The method of claim 1 , wherein causing the first user interface to be displayed as the overlay on the first web page includes causing the first user interface to be displayed as a bar overlaid on the first web page.

9. The method of claim 8 , wherein the first user interface includes a set of content-sharing tools that enables content from the first web page to be shared by the first member with the second member from the set of members of the first online community.

10. A computer-readable storage medium storing a plurality of instructions for controlling a processor to provision instant communication services, the plurality of instructions comprising:

instructions that cause the processor to facilitate, by a first domain, instant communications for a first online community, the first online community operating from a second domain different from the first domain;

instructions that cause the processor to generate an instant communication session associated with a first web page accessed by a first member of the first online community, the first web page from a website of the first online community;

instructions that cause the processor to cause a first user interface to be displayed as an overlay on a first web page, the overlay covering a portion of the first web page, wherein the first user interface includes a chat window enabling the first member to exchange messages with a second member from a set of members of the first online community and a list window displaying at least one member from the set of members, the list window adjacent to the chat window;

instructions that cause the processor, responsive to a second web page being accessed by the first member, to retrieve session state information associated with the instant communication session and the messages exchanged between the first member and the second member, the second web page from the website of the first online community;

instructions that cause the processor to preserve, based on the session state information, the instant communication session from the first web page to the second web page by causing the same first user interface, including the chat window and the adjacent list window, to be overlaid on the second web page, the session state information describing a status of the instant communication session and including information describing one or more messages sent by the first member, the second web page accessed by the first member and from the website of the first online community;

wherein the facilitating enables the first member of the first online community to exchange one or more messages with the second member of the first online community using an instant communication technology;

instructions that cause the processor to facilitate, by the first domain, instant communications for a second online community, the second online community operating from a third domain different from the first and second domains, wherein, for a user who is a member of the first online community and the second online community, the user has a first list of friends for the first online community and a second list of friends for the second online community; and

instructions that cause the processor to cause an aggregated list of friends to be displayed on the first web page accessed by the user from the website of the first online community, the aggregated list of friends comprising one or more friends in the first list of friends and one or more friends in the second list of friends.

11. The computer-readable storage medium of claim 10 wherein the instant communication technology uses instant messaging (IM).

12. The computer-readable storage medium of claim 10 wherein the plurality of instructions further comprises:

instructions that cause the processor to store, at a system in the first domain, the session state information for the first member, the session state information comprising information related to the first user interface.

13. The computer-readable storage medium of claim 10 wherein the instructions that cause the processor to cause the first user interface to be displayed as the overlay on the first web page comprise:

instructions that cause the processor to, for at least one member of the first online community:

display presence information for the member; and

display status information for the member.

14. The computer-readable storage medium of claim 10 wherein the instructions that cause the processor to cause the first user interface to be displayed as the overlay on the first web page comprise:

instructions that cause the processor to display a notification sent to the first member from the second member of the first online community.

15. The computer-readable storage medium of claim 10 wherein the instructions that cause the processor to facilitate instant communications comprises:

instructions that cause the processor to provide a first set of application programming interfaces (APIs) for the first domain, the first set of APIs being callable from the second domain for exchanging information with the first domain; and

instructions that cause the processor to provide a second set of application programming interfaces (APIs) for the second domain, the second set of APIs being callable from the first domain for exchanging information with the second domain.

16. The computer-readable storage medium of claim 10 wherein

the facilitating enables a third member of the second online community to exchange one or more messages with a fourth member of the second online community using the instant communication technology.

17. A system comprising:

a memory; and

a processor coupled with the memory, the processor configured to:

facilitate instant communications for a first online community, thereby enabling a first member of the first online community to exchange one or more messages with a second member of the first online community using an instant communication technology;

generate an instant communication session associated with a first web page accessed by the first member of the first online community, the first web page from a website of the first online community;

cause a first user interface to be displayed as an overlay on the first web page, the overlay covering a portion of the first web page, wherein the first user interface includes a chat window enabling the first member to exchange messages with the second member from a set of members of the first online community and a list window displaying at least one member from the set of members, the list window adjacent to the chat window;

responsive to a second web page being accessed by the first member, retrieve session state information associated with the instant communication session and the messages exchanged between the first member and the second member, the second web page from the website of the first online community;

preserve, based on the session state information, the instant communication session from the first web page to the second web page by causing the same first user interface, including the chat window and the adjacent list window, to be overlaid on the second web page, the session state information describing a status of the instant communication session and including information describing one or more messages sent by the first member, the second web page accessed by the first member and from the website of the first online community;

wherein the system is in a first domain and the first online community is maintained by a second domain different from the first domain;

facilitate instant communications for a second online community, the second online community operating from a third domain different from the first and second domains, wherein for a user who is a member of the first online community and the second online community, the user has a first list of friends for the first online community and a second list of friends for the second online community; and

cause an aggregated list of friends to be displayed on the first web page accessed by the user from the website of the first online community, the aggregated list of friends comprising one or more friends in the first list of friends and one or more friends in the second list of friends.

18. The system of claim 17 wherein:

the memory is configured to store the session state information for the first member, the session state information comprising information related to the first user interface.

19. The system of claim 17 wherein the processor is configured to:

cause presence information for at least one member of the first online community to be displayed in the first user interface;

cause status information for at least one member of the first online community to be displayed in the first user interface.

20. The system of claim 17 wherein the processor is configured to:

cause a notification sent to the first member from the second member of the first online community to be displayed in the first user interface.

21. The system of claim 17 wherein

the facilitating enables a third member of the second online community to exchange one or more messages with a fourth member of the second online community using the instant communication technology.