Facebook, is it becoming a mission critical service for you?

Nick O'Neill in "When Facebook Closes Your Account" seems to think that Facebook is moving into the category of online service that is mission critical. He says:

I now perform a large chunk of my business activities via Facebook. It's pretty crazy how rapidly Facebook has become a mission critical communication tool for me even though their message searching features are non-existent.

So is it becoming mission critical for you?

I know there are just so many applications that you can use on Facebook, for example, I do all my news reading using the tool "myRSS", and I listen to NPR Podcasts via the NPR Pocast player, and then when I need to use Zoho I turn to it from within Facebook. Mission critical? Possibly not for me yet but it is coming close.

Facebook still has some reliability issues which makes me think that regardless of how many applications are available in Facebook I need to spread my risk by using other services rather than the facebook applications.

Let me know in the comments, Is Facebook mission critical for you yet?