AFF is a community of readers, writers, and lurkers. If you are a consumer looking for a good read (not unless you can do so yourself and you have talent unearthening those hidden gems in this site), you go to recommendation fanfic-blog-posts-etc. But if you are a writer who thinks you need constructive feedback (or just expecting praises for your work since you aren't satisfied with the comments of your loyal readers), it is most probable that you will search for a review shop. But come on, you think your story will be advertised in a way once that shop updates its shop with the review of your story so I'm thinking that's one of your reasons as well. 

But if you think that you seriously need some real feedback for your piece because you want to improve, you  have plans to publish it in a hardcopy and be Rowling-famous, you think you are destined to be a writer, or simply cannot imagine yourself doing any other occupation in the future than just sit inside your house and drown yourself with overflowing words in front of your monitor, shutting yourself away from the outside world, then it's not that far that you will look for a review shop in this site. But how credible are the review shops in this website? Here are my theories why review shops have been sprouting left, right, front and back:

• They want to help writers improve.
• They have too much opinion about every story (and simply everything) and they're so thrilled to voice out their thoughts.
• They need karma points which they gain everytime they post your fanfic's review (and don't be surprised if it's only a one-liner because they simply don't care if you improve or not, all they're after are points, points, points). And don't be shocked if they're writers who originally have another account, I bet they're planning to use the karma points for advertisement, and etc. Because, how will they use karma points, for changing username? Donating? Bizh please.
• They are just there to insult your story and of course, to gain karma. (And if you happen to choose this kind of review shop, don't take their "criticism" to the bones because they will just damage your esteem as a writer, you will start to think you aren't good enough, you get discouraged, you'll stop updating, readers will complain, they unsubscribe, you get discouraged, you continue to think you aren't good enough, you leave the site, you get forgotten, you log in again, you forgot your password, you sign-up with a different username, you have zero karma points, you write again...and before you know it, it's the end of the world - zombies, natural disaster, etc.)
• And again, they want to help writers improve.

The first and the fifth bullets can be difficult to find.

Of course, they'll tell you 'If you can't handle criticism, then don't even think of asking for a review'. Again, Bizh please. Writers ain't stupid. There is a fine line between a helpful, constructive criticism and dissing. Of course, you can be harsh, but it ain't right if you deduct 'points of rubrics' just because you didn't like the characters, writing style, etc. (I'm gonna discuss this later). Who even invented that point system? Will there be a graduation day and someone gets awarded summa/magna laude?

I don't know if you have read this somewhere but 'REVIEWING IS A JOB FOR READERS'. Of course, writers are readers too. But you can't review and criticize someone's style from your writer's perspective. Also, this site is not a publishing house filled with professional editors and critics to do the job. What we have is the pool of users in this site. Although we need qualified reviewers to do the job, there must still be an extent as to how someone can be qualified as a reviewer. Factors include experience in the field, college major, first-language designation, number of books read (slightly doesn't make sense but it does, but you'll most likely be at loss if that reviewer had read Picoult, Shakespeare, etc due to their high expectation), but I'm not saying that being a reviewer should be exclusive to native-speakers because non-native speakers can do the job as well. 

So is this payback? Only you can tell. You tell writers to provide a good show to the readers. But guess what, fanfic reviewers need to get their lives straight too.

And how qualified am I to do this kind of thing? Am I merely a disgruntled writer who's plotting this payback for the review shops who caused me 'harm'? How did I decide to create this? I have read English novels and scientific journals all through-out my college years and currently working, and I will be opinionating and recommending review shops, not fanfics. I haven't posted anything in this site but I would love to in the future; hadn't asked for any review. You could say I like browsing at recommendation shops, and most of them are review shops as well. I also look at the reviews they're making, and it made me wonder why some reviews are good, and some sound like some rant or something...and then I realize that the latter kind is just being a pain in the .

REVIEWING IS NOT SO-SO. IT'S A COMMITMENT.