For me, it would depend on the reason I left. If I were busy, I'd post and tell it - but then, I'd come back again.

If something terrible happened, I would probably not post anything for a while, but eventually, I'd let people know. Especially the ones I like and am close to. In the last case, I'd probably ask someone to tell the rest.

If everybody I like left, I'd most likely leave quietly.

But, I'm not leaving!