Ever since the early days of the Fail Whale, Twitter has earned, perhaps rightly, a reputation of not being the stablest of web services. The advent of today’s “forced follow” Twitter bug, which allowed users to very easily force anyone to follow them on Twitter, is not likely to help that reputation — nor is the fact that in combatting it, Twitter has temporarily reset follower and following counts to zero.

As you’ve no doubt heard, Google signaled its move into the social media arena in a big way at 10am PST today by announcing the launch of Google Buzz, a Gmail-integrated social networking utility which will roll out over the next few days.

So: what is Google Buzz, exactly? Below, ten things that define what it is — and what it isn’t: