Just launched. Free service to get updates when repos you watch are updated with new tags. You can select which ones you want notifications for and how often you want emails. Currently only support Github, but if enough demand, we can add support for BitBucket.

For those who are wondering the purpose, Github's newsfeed isn't enough to really know when repos are updated. The ideas is to choose repos you use often, say Twitter Bootstrap, htmlpurifier, etc and then you can update however you are using these repos into your projects.

Hope you guys find it useful.