Tracking mobile app installations

1. A data processing method comprising:

receiving, at a mobile computing device, a request comprising a protocol identifier, a label value, and a data value, wherein the protocol identifier is associated with a protocol implemented in a first mobile app;

using a protocol handler in the mobile computing device associated with the protocol, initiating processing of the request;

using a native code element in the mobile computing device: intercepting the request from the protocol handler when the label value matches a particular expression, and in response to the intercepting, providing a unique identifier associated with the mobile computing device to other than the first mobile app, the protocol handler or the native code element;

wherein the method is performed by one or more computing devices.

2. The method of claim 1 wherein the providing comprises providing the unique identifier to a second app in the mobile computing device.

3. The method of claim 1 wherein the providing comprises providing the unique identifier to a server computer using a callback.

4. The method of claim 3 further comprising receiving the request in response to selecting a link in a web page that is served from the server computer.

5. The method of claim 1 further comprising receiving a plurality of other requests each comprising a different protocol identifier, the label value and the data value; determining whether the protocol identifier matches any protocol handler registered in the mobile computing device; performing the processing, intercepting, obtaining, and providing in response to determining a first match of the protocol identifier to the protocol handler from among all the protocol identifiers.

6. The method of claim 3 further comprising:

the server computer sending a plurality of requests to the mobile computing device, wherein each request in the plurality of requests comprises a different protocol identifier, the label value and the data value;

determining whether the different protocol identifier in each request matches any protocol handler registered in the mobile computing device;

performing the processing, intercepting, obtaining, and providing in response to determining a first match of any of the different protocol identifiers to the protocol handler.

7. The method of claim 3 wherein the server computer is associated with an advertising network.

8. The method of claim 1 further comprising causing the first app, linked with the native code element as part of a software development kit (SDK), to be installed on the mobile computing device.

9. The method of claim 4 wherein the data value comprises a click key indicating a function in the web page that was selected.

10. The method of claim 1 wherein the particular expression is a regular expression that matches functions of a service provider associated at least in part with registering to receive advertisements.

11. The method of claim 1 , wherein the providing comprises providing the unique identifier to a second app in the mobile computing device; further comprising causing the second app to perform a re-engagement operation.

12. One or more non-transitory storage media storing instructions which, when executed by one or more computing devices, cause performing:

receiving, at a mobile computing device, a request comprising a protocol identifier, a label value, and a data value, wherein the protocol identifier is associated with a protocol implemented in a first mobile app;

using a protocol handler in the mobile computing device associated with the protocol, initiating processing of the request;

using a native code element in the mobile computing device: intercepting the request from the protocol handler when the label value matches a particular expression, and in response to the intercepting, providing a unique identifier associated with the mobile computing device to other than the first mobile app, the protocol handler or the native code element.

13. The storage media of claim 12 wherein the providing comprises providing the unique identifier to a second app in the mobile computing device.

14. The storage media of claim 12 wherein the providing comprises providing the unique identifier to a server computer using a callback.

15. The storage media of claim 14 further comprising instructions which when executed cause receiving the request in response to selecting a link in a web page that is served from the server computer.

16. The storage media of claim 12 further comprising instructions which when executed cause:

receiving a plurality of other requests each comprising a different protocol identifier, the label value and the data value;

determining whether the protocol identifier matches any protocol handler registered in the mobile computing device;

performing the processing, intercepting, obtaining, and providing in response to determining a first match of the protocol identifier to the protocol handler from among all the protocol identifiers.

17. The storage media of claim 14 further comprising instructions which when executed cause:

the server computer sending a plurality of requests to the mobile computing device, wherein each request in the plurality of requests comprises a different protocol identifier, the label value and the data value;

determining whether the different protocol identifier in each request matches any protocol handler registered in the mobile computing device;

performing the processing, intercepting, obtaining, and providing in response to determining a first match of any of the different protocol identifiers to the protocol handler.

18. The storage media of claim 14 wherein the server computer is associated with an advertising network.

19. The storage media of claim 12 further comprising instructions which when executed cause causing the first app, linked with the native code element as part of a software development kit (SDK), to be installed on the mobile computing device.

20. The storage media of claim 15 wherein the data value comprises a click key indicating a function in the web page that was selected.

21. The storage media of claim 12 wherein the particular expression is a regular expression that matches functions of a service provider associated at least in part with registering to receive advertisements.

22. The storage media of claim 12 wherein the providing comprises providing the unique identifier to a second app in the mobile computing device; further comprising causing the second app to perform a re-engagement operation.