Google could have bought Twitter for $5 billion a few years ago,
but it was too focused on its own social network Google+ and it
passed, according to venture capitalist/blogger Michael
Arrington.  Arrington was interviewing fellow VC Fred Wilson at
TechCrunch Disrupt.  He dropped that nugget of information as a
question, saying something to the effect of, I've heard that
when Twitter was raising its most recent round, in the 5-range,
CEO Dick Costolo went to Google and said you could own us, but
Google was too busy with Google+ .  Wilson didn't confirm or
deny Arrington's comment, but he did say that Google has not
been interested in Twitter since it started Google+.  Google+,
while only a year old, is seen as a big flop, and a "ghost
town." It's treated with scorn by critics. (Why? It seems to
stem from the fact that Google shoved it down user's throats.)
If it had an opportunity to buy Twitter for $5 billion, it
probably should have done it.