Wow, what a thread!
Something that I learned by personal experience when I was a kid is that you could achieve excellent spelling, grammar and syntax by just reading well-written books. The more you read, the better you get, no matter how much you hate language classes at school. My first language is Spanish, so when I decided that I wanted to learn English I basically applied the same formula: read, read, read. By reading, you're exposed to a language in its purest form. Learning a language (your own or otherwise) using a text book is much more boring anyway.
My approach to photography has been the same, at least so far. Even after receiving some formal (basic) training, the best way for me to learn has been by just looking at photos, and more photos every day. The first thing you learn this way is composition (what works, what doesn't, some conventional rules, etc.); then aperture and shutter speed, proper exposure, and so on. This is, in my opinion, the strength of forums like TPF, and not necessarily the feedback that your images may or may not receive when you post them.
So my humble recommendation (especially to the very beginners) is: don't expect the knowledge to be given to you –keep in mind that the person critiquing our photos might be even more clueless than we are. Instead, go for it! "Absorb" as many photos as you can, and of course shoot a lot. In a matter of just a few weeks you'll notice that your eye is able to distinguish between good and bad images, an acquired "gift" that you'll find yourself applying to your own work in no time. Doing research or reading a text book or two won't hurt either. The rest will come.
That being said (rant alert!), I think there are quite a few arrogant jerks on this forum (just like everywhere else) who feel that they put themselves in a higher place when they dismantle other people's photos. As noted, a blunt "that doesn't do anything for me" or "it's an OK photo but I've seen it many times" can be very disheartening, no matter your level of knowledge. The truth is, those arrogant comments say more about the "expert" than about the photos. (The most striking thing about these jerks is that they rarely post any images themselves.)
Sorry for the long post. I got carried away and I'm not even sure if I said anything of substance.