You can watch activities regarding proposals, tags, instances and users. Watching means that you are notified of any changes in the respective area.
To get notifications click on the watch
button in the upper right corner.
Click on the Settings
link in the upper right corner to get to your
profile page. Under Notifications
you can choose how
detailed you want your notifications to be.
Notifications via e-mail and via twitter are implemented so far. More possibilities will be added in the future.
In your watchlist (link in the upper right corner) you can see which proposals, users, instances and tags you are watching.