It doesn't seem to show answers being posted but then deleted, even though I can see the deleted answer.
Generally speaking though, it looks very handy. The triangles are a bit ugly, but it's functionally great :)
EDIT: Okay, I've just tried creating and deleting a second answer for this question here on meta - again, I can't see it. I know you don't want hugely detailed bug reports, but consider this a vote to be able to see that information (users with enough rep).
In terms of other feedback...
I'm not sure I'd make it another tab, because it's not just a different sort order for the answers. I'd consider making it another link next to "edit / close / flag" at the bottom of the question.
The nature of the URL suggests that it should be feasible to show the timeline of just an individual answer as well. In some cases this could be very useful, rather than having to mentally filter out all the bits that for other answers. If this became available, again it could be another link in the "link / edit / flag" set.
