> Since every project is isolated, how do you handle operations that require data from multiple projects, such as the activity feed or merge requests?

Right now: Poorly.

But in a few months: - We're adding an activity feed API to Sandstorm, so that you can get a unified feed and notifications across all apps. - The Powerbox (https://sandstorm.io/how-it-works#powerbox) allows connecting grains to each other. We will define a git API which each of the git apps (Gitlab, Gitweb, Gogs) can implement, so that you can even do cross-app merge requests.