Problem: My GitHub account is associated with one of my personal email addresses, but I use it (a lot) for work. A pull request notification on that JavaScript route mapper I wrote isn't that important, but an issue or pull request on the Typekit web app or one of our gems is fairly important. Those emails need to end up in my work e-mail box — that's the context I want them in, so I can be more free to ignore whatever is going on outside of work when I'm working.

37signals solves this problem in Basecamp by letting you select a particular email address to use for each account you have access to. GitHub doesn't offer much control over email notifications yet, unfortunately, but they do include some very useful headers in their emails that make effective filtering way easier:

List-Archive: https://github.com/typekit/webfontloader
List-Id: <webfontloader.typekit.github.com>

List-Id headers are always of the form reponame.accountname.github.com. My aforementioned Björn project would be bjorn.ddemaree_old.github.com.

In Gmail you can find (and therefore filter) all emails from a given account by setting up wildcard queries on the List-Id header, which Gmail helpfully lets you search on via the list: search operator:

Obviously this will work best if all of the repos whose emails you want to filter are owned by a single account, or at least a small, known list of accounts. (In that case you'd change your query to list:"*.(account1|account2).github.com".)

You could also just search on the subject lines, which always include the repo or project name in square brackets. But whenever we added a new project to our account, or someone issued a pull request for a repo I hadn't filtered yet, those emails would end up in the wrong place until I corrected the problem. This way all GitHub notifications related to the typekit account go to my Typekit email box, with no further action needed from me.