Does Mercurial offer any type of extensions that offer functionality similar to TFS's work items that when you check in changes that you can associate them to features/defects?
If there isn't much (or any) support for this, how do you handle ALM using Mercurial?
What you may be looking for is called a distributed bugtracker. There is a number of those available on top of that or another dvcs.
I've come across a couple of links: