Displaying additional external video content along with users participating in a video exchange session

1. A method comprising:

receiving a creation request for establishing a video exchange session from a requesting user at an online system, the creation request identifying one or more other users to exchange video content with the requesting user;

receiving, at the online system, a request for an interface of the video exchange session to include external video content from an external source other than users participating in the video exchange session;

generating, by the online system, the interface of the video exchange session, the interface including regions associated with each user participating in the video exchange session, a region associated with a user displaying video content the online system receives from the user, and an external region in which external video content the online system receives from the source other than the users participating in the video exchange session is displayed; and

transmitting the interface from the online system to client devices of one or more users participating in the video exchange session.

2. The method of claim 1 , wherein receiving, at the online system, the request for the interface of the video exchange session to include external video content from the external source other than users participating in the video exchange session comprises:

receiving a selection of an activity for the video exchange session, the activity specifying one or more external sources other than the users participating in the video exchange session for the external video content.

3. The method of claim 2 , wherein the online system stored multiple activities for the video exchange session, different activities specifying different external sources other than the users participating in the video exchange session for the external video content.

4. The method of claim 2 , wherein the activity is associated with a template specifying a location within the interface for the external region.

5. The method of claim 1 , wherein the external source comprises content stored by the online system.

6. The method of claim 5 , wherein the content stored by the online system comprises video content that displays in a loop.

7. The method of claim 1 , wherein the external source comprises a third party system.

8. The method of claim 7 , wherein the content stored by the online system comprises video content that displays in a loop.

9. The method of claim 1 , wherein the external source comprises an alternative user of the online system.

10. The method of claim 1 , wherein receiving, at the online system, the request for the interface of the video exchange session to include external video content from the external source other than users participating in the video exchange session comprises:

receiving, at the online system, an identifier of the external source.

11. A computer program product comprising a non-transitory computer-readable storage medium having instructions encoded thereon that, when executed by a processor, cause the processor to:

receive a creation request for establishing a video exchange session from a requesting user at an online system, the creation request identifying one or more other users to exchange video content with the requesting user;

receive, at the online system, a request for an interface of the video exchange session to include external video content from an external source other than users participating in the video exchange session;

generate, by the online system, the interface of the video exchange session, the interface including regions associated with each user participating in the video exchange session, a region associated with a user displaying video content the online system receives from the user, and an external region in which external video content the online system receives from the source other than the users participating in the video exchange session is displayed; and

transmit the interface from the online system to client devices of one or more users participating in the video exchange session.

12. The computer program product of claim 11 , wherein receive, at the online system, the request for the interface of the video exchange session to include external video content from the external source other than users participating in the video exchange session comprises:

receive a selection of an activity for the video exchange session, the activity specifying one or more external sources other than the users participating in the video exchange session for the external video content.

13. The computer program product of claim 12 , wherein the online system stored multiple activities for the video exchange session, different activities specifying different external sources other than the users participating in the video exchange session for the external video content.

14. The computer program product of claim 12 , wherein the activity is associated with a template specifying a location within the interface for the external region.

15. The computer program product of claim 11 , wherein the external source comprises content stored by the online system.

16. The computer program product of claim 15 , wherein the content stored by the online system comprises video content that displays in a loop.

17. The computer program product of claim 11 , wherein the external source comprises a third party system.

18. The computer program product of claim 17 , wherein the content stored by the online system comprises video content that displays in a loop.

19. The computer program product of claim 11 , wherein the external source comprises an alternative user of the online system.

20. The computer program product of claim 11 , wherein receive, at the online system, the request for the interface of the video exchange session to include external video content from the external source other than users participating in the video exchange session comprises:

receive, at the online system, an identifier of the external source.