[missn]

One might argue that knowing all these "catch-up" details beforehand (through Facebook) could allow for more deep conservations when people meet up - they can immediately dive into the deep stuff and skip the catching up part.

Yet, as you've mentioned, small talk leads to many more tangents than what you'd usually get online. And, if you actually eavesdrop on conservations (or even look at your own), they usually start slow with small talk but eventually build up momentum towards deeper issues.Sometimes we just need time to settle in a conservation and those "what's up" starters usually help in that regard.