This is something we are testing out to help communities gauge how they're doing and for us (the community team at SE) to be able to check on the quality of the sites we may not be very familiar with. I wrote more about this here, but the main point is this:
Think of it as a periodic sanity check and a way to make sure that the site's still doing well. Are the questions of high quality? Are the answers better than what someone can easily find through Google?
What we see a lot on various sites is that someone will bring up a specific question for review, but it's incredibly rare for someone to initiate a broader discussion. That is what these evaluations are supposed to facilitate.
The results aren't something just for moderators to review and act on. Anyone can and should check on them as well.
For you as a site user there are two main ways to look at the results:
Look at the individual outcome for specific questions. If many people think a question "needs improvement", consider whether you can help improve it. Or maybe it's unsalvageable and should be closed.
Look at the patterns among the various questions. Is there a particular kind of questions that's getting good reviews? Bad reviews? Perhaps some specific type of questions should be discouraged and a meta discussion can be opened about making them officially off-topic.
Above all else, if/when you see your own questions pop up under review (although we should probably make sure you can't review your own questions), keep in mind that this review isn't personal. Try to learn from the opinions of the other users as much as possible. If your question is getting a great review, awesome! Ask more questions like it. If it's getting a bad review, consider why that might be the case. Maybe it needed more detail, maybe it was just too obvious... If all else fails, you can always ask here on meta for help or drop by the chat and see if you can get some specific feedback.
We are going to be rolling out a better set of instructions and a way for folks to (hopefully easily) discuss questions and answers that are under evaluation soon, so stay tuned for that.