Forget about "talk", what about MIT's Zephyr (Score 2, Informative)

MIT has had a instant messaging system for years before ICQ came out.
It has been in use in other major universities including Caltech and
Stanford.

This system is called Zephyr.
http://web.mit.edu/answers/zephyr/
http://web.mit.edu/olh//Zephyr/

There is a web page that describes the similarities and differences
between ICQ and Zephyr (and notes that Zephyr came first)
http://web.media.mit.edu/~kkarahal/generals/VSpace s/zeph-icq.html

The differences are subtle and probably inconsequential;
I believe the similarities nullify the value of the patent.