And if you aren't interested in that, don't fret; reviews (complete with star ratings) continue on Monday.
I dislike trying to assign reductivist ratings (star ratings, thumbs up/down, decimal scoring, etc.) to fanfiction. The main problem with them is, as the name itself states, that they're inherently reductivist: they amalgamate every aspect of a story's perceived quality into a single number, which is somehow supposed to represent the worth of a piece of writing. This makes that number minimally useful to anyone trying to gauge the merits of a story based solely on that number, because different people weight different aspects of stories differently. If I say to someone, "Story X has show-accurate and surprisingly nuanced characterizations, but there's no central conflict to tie the piece together and the ending is a hasty attempt to reassert the status quo," then that gives them some useful information to help determine whether or not they'd enjoy reading it. If I say to them, "I gave Story X two stars," that's only useful insofar as they're able to determine how likely we are to have common taste in writing.
Now, it's true that the first example also requires a certain amount of functional comparison; what I call "a hasty attempt to reassert the status quo," someone else might consider a perfectly valid return to normalcy at the denouement. But I think it goes without saying that this is still patently more useful than a reductivist rating alone.
Furthermore, reductivist ratings invite comparisons which are often inapt. Heck, I make it incredibly easy to do exactly that, by having a link at the top of this site to a page listing all my reviews sorted by star rating. Vengeance and Fashion got four stars, while The Misted Stage only got three? That must mean Vengeance is a better story, right? Of course, comparing these two is about as sensible as comparing The Hitchhiker's Guide to the Galaxy with A Wrinkle In Time, or arguing the merits of Airplane! versus Planet of the Apes. It's true that some people will try to do precisely that anyway, but it's a silly argument no matter what; you're comparing two things which are sufficiently different that they need to be judged on their own merits, not in relation to each other.
But as I said, reductivist ratings not only allow for these kinds of comparisons, they encourage them. So why do I bother with star ratings in the first place, if they cause so much trouble?
For one thing, they make my job quite a bit simpler. My reviews can get a bit disorganized (as you may, just perhaps, have noticed), and putting a star rating at the end gives me a chance to sum up the major successes and faults of a story in a way that makes reasonably clear which I thought were more prevalent. At the end of a review (as opposed to in place of one), I think they can provide a conclusion more coherently, if probably less effectively overall, than words alone. Moreover, people like ratings; they're nice, clean, concrete things to hold onto, to argue about or to nod in agreement with. The list of reviews by star rating? That wasn't part of the site for the first couple months I was doing reviews. I added it because visitors kept e-mailing to ask if I'd put one up.
I don't like trying to assign a numeric value to a story, and I really hate doing it when I give out a low number (especially to stories that I like, or at least that I like more than the low rating seems to me that it indicates). But despite the flaws any sort of reductivist rating brings to the table, I'm of the opinion that they also provide an excellent jumping-off point for discussions, a convenient shorthand for summary statements, and are fundamentally appealing to most people. So although they frustrate me at times (especially when I've been staring at an open review doc for twenty minutes, rereading my notes and occasionally pulling the story back up, trying to decide if a given fanfic merits two or three stars, and I suddenly become aware that this is what I do for fun), I plan to continue giving star ratings to the 6-star stories I review.