I don't know. In 1996, I think this would have been pretty novel. The idea of parsing a random block of text and converting everything that looked like a phone number certainly didn't exist in any device or software I can think of. I don't remember any email or IM clients detecting email addresses and making them links either.
Some software patents are in fact valid inventions. The fact that today, 15 years later, it seems obvious, doesn't mean it was at the time.
I was 17 at the time, and heavily into computers, programming, and the Internet as a hobby. Far from being novel I thought this idea falls into the "bleeding obvious" category.
I guess how you'd accomplish it is pretty obvious, but the idea of linking phone numbers in text is not. There was no pressing need to do so at the time. Once a lot of text messages are happening and people start sending phone numbers and email addresses to each other, it becomes obvious.
Of course, I'm not sure the idea is patentable, only the implementation.
Some software patents are in fact valid inventions. The fact that today, 15 years later, it seems obvious, doesn't mean it was at the time.