This Wikipedia Article Is Not Yet Rated
Even if you're a very casual Wikipedia reader (which I assume is not the case, or you wouldn't be here right now) you might have noticed a few new features* at Wikipedia in recent weeks and months. Most noticeably, the Article Feedback Tool, pictured below.

And it takes a single click to see the ratings on a given article. In the following example, a number of readers have already expressed their opinion of the (very short and currently unreferenced) article about the new Clap Your Hands Say Yeah album, which isn't supposed to be released until later this month (thanks, Spotify / BitTorrent!).

It's not entirely clear what the long-range prospects for the tool may be. Unlike flagged revisions, it isn't slated for a vote and approval or removal; indeed, it's now listed on every Wikipedia article that you visit, and it will continue to be for the indefinite future.
But that doesn't mean it will necessarily remain static. An invitation to "please take a moment to rate this page" has already been changed. More questions are surely in store, especially as some very good questions have been raised, such as who's to say what it means to be "highly knowledgable" in a given subject area?
Certain aspects of its implementation, though, are quite clever. For example, any rating assigned to an article that itself may change often cannot be considered good for long, right? This has been anticipated: ratings expire after 30 edits have been made on a given page, and if you've rated a page before, you can re-rate it then.
Some Wikipedians have also asked for a statistical tool charting the data over time, which would be very cool to see. Like most Wikipedia projects, all information captured is available through its API, so anyone could build one if they wanted. A good example of this kind of ad hoc service is User:Henrik's Wikipedia article traffic statistics tool.
Meanwhile, it also opens a new Pandora's box for Wikipedia (as if it didn't already have plenty). Perhaps the biggest concern ahead is that the ratings can be gamed; as Liam "Wittylama" Wyatt (known particularly for his work with the British Museum) has pointed out, the top-rated article (4.9 out of 5 stars) is something called the VAD 43 MRC Klang Chapter. About which, well, have a look for yourself.
I think the concept of article ratings is an idea whose time is coming, if that time is not yet now. These ratings have a long way to go before they should be considered a barometer of anything. It's a good start, but still just that.
*The other is one asking how you feel about editing Wikipedia, complete with a choice of smiley and frowny faces, but I haven't seen it lately.