As a user it's definitely somewhat disheartening. It seems like whenever something cool/useful comes from a small, previously unknown team, there's a significant chance that it'll just be bought and killed by a big player. Both makes me more wary of relying on such services to begin with (even if they're paid!), and from a progress-of-technology perspective feels unfortunate. I'm sure it's great for the founders, but it's like big companies are using their cash pile to do the opposite of encouraging technological progress: find technological progress elsewhere, buy it, and axe it.

Things do occasionally turn out okay, e.g. Google allowed the EtherPad team to open-source the code after Google bought/killed it. And, although I don't personally use/like it, Dodgeball got more or less resurrected as FourSquare after Google bought/killed it.