The deployment cluster is where we are encouraging the community to test the new code before we deploy it on the live sites. We are hoping to track down problems now, before they affect people.
We have tried our best to test the software before it gets to this point (we use Code review and Unit testing to systematically test the code), but we can't anticipate all the ways that the software is used.
That is where you come in.
If you normally use a gadget, try it out here. Make sure it works and report any problems.
If you think that there is something missing here that you'd like to test before we deploy this software, please let us know so we can set it up here.
Try uploading images to the Wikimedia Commons beta project or using the slideshow gadgets. Try editing an article or patrolling one. Try rolling back edits.
Consider this cluster a huge sandbox. Nothing you make on the *.beta.wmflabs.org sites should be considered permanent and it may be removed at any time.