What is your typical source control commit comment?
What are suitable comments to put in the source control log? To me this seems a similar problem (but possibly more difficult) to how to comment source code itself. For commenting code, it is considered important not to duplicate information that is in the code itself. That is to say the code should be explanitory enough to say what/how it is doing. If your comments do the same thing then you have redundant information that you have to keep up todate [cite: DRY principal; The Pragmatic Programmer; Hunt, Thomas -1999]
Now for version control repositories you have access to functions such as Blame, Praise or Annotate (depending on system); as well as the ability to Diff versions. So you can work out exactly what has been done.
So the Broad idea of what should go in a source controls log is to talk big picture. Stuff that would let people pick out which version to Diff with to find what actually happened. (And then they would use the results of the Diff to be certain whether this was the version they were Actually interested in). So avoid saying "Added functon X to class Y" or "Renamed class Z to W", because the can be found out by Diff'ing, and more so the information you would get from doing a Diff is more useful/complete. Eg you would know exactly what function X does.
So I guess I have a picture of what the answer already is, but can anyone with more exprience using a long running version control illuminated on what comments are actually useful, and also what are practical to put in?
I guess this would apply, even, to comments on changes in Wiki or edits in Stack overflow aswell.