I think that hearing parts of a conversation are actually part of the viral nature of Twitter. By hearing about your friends’ friend, you can expand your network and find other interesting people.

It’s also why people use Aliases instead of names when replying, so that others can follow the links and add new friends.

In this particular case, however @PhilMorle is not very interesting so don’t bother adding him haha.

Just kidding of course - it would be nice to have this feature, but I also think it’s one of those things that, by it’s not being there, actually makes the community stronger over time - even though it seem counter-intuitive.