We have added some new features for users that want to run builds and continous integration from Assembla repositories, and it's just in time, because we started getting questions by email about how to set up continuous integration.  Here are a few hints:

Make a script user
Your build scripts will usually need to provide a username and password to checkout code from the repository.  Do not put your own username and password in the scripts.  Instead, register a new user, like "assembla_deploy_scripts", and add that user to your team.  Remember to log in as this fake user and "Accept" the team invitation, because Assembla will remove the team membership if it is not accepted within 10 days.

Use the continuous integration trigger
If you are a fan of continuous integration, you want to run a build or test every time someone commits new source code.  Your build system needs to be notified to run the build or test.  You can configure Assembla to make an HTTP GET request that will trigger the build script, when there is a new commit.  Go to the Trac tab on the space (Trac includes Subversion), on the bottom, and put in the URL of a script that will run the build.  Assembla will get this URL after each commit.  It is your responsibility to configure your web server to run the correct scripts when this URL gets called.

IP Security
A user requested that access to svn and trac be restricted to certain IP ranges used by his clients.  So, we implemented this as a premium feature for commercial spaces. You will find a new "Allowed IP address" field on the Admin/Security tab of a space.

The future
In the future we will support external repositories and, in a big jump forward, virtual servers.  In theory you should be able to push a button, instantiate a virtual server, and test both your upgrade/migration process and the new version of the application.  When we get this rigged up it will eliminate a LOT of maintenance headaches.