It would be very useful to be able to quickly open a commit (from log/history) on Bitbucket in a browser or have a link for it.

Given that SourceTree is also an Atlaassian product it's surprising that there is no such feature (or it's very well hidden).

I'm sure there is a way to make a custom script by finding the .git folder and determining the repo's Bitbucket URL from a corresponding Bitbucket remote. But I think this deserves to be a part of SourceTree itself. Feel free to close this feature request if you think otherwise.