I noted that in BitBucket when your commit log contains a number like #12 this number is linked to the bug number 12.
I found this feature interesting, and
Google Code Project Hosting also supports it:
http://code.google.com/p/support/wiki/IssueTracker#Integration_with_version_control
There are commit-log commands to:
Request a code review.
(Fixes issue NNN) Enclose command in parentheses
Fixes issue NNN. Full sentence in your log message description
Fixes issue NNN On a line by itself
The word Fixes can replaced with Closes or Resolves. The issue number can have a leading pound-sign (#) or not.
The other commit-log commands use a multi-line "long form" syntax that is more powerful.
COMMAND-LINE
ISSUE-FIELD-UPDATE*
COMMENT-TEXT...
Where COMMAND-LINE is one of the following:
Update issue NNN
New issue
New review
There can be any number of ISSUE-FIELD-UPDATE lines. These lines can be one of the following:
Summary: NEW-VALUE
Status: NEW-VALUE
Owner: NEW-VALUE
Cc: PLUS-MINUS-LIST
Labels: PLUS-MINUS-LIST