With the self-promotion thing, I agree that if you want to get your stories seen and build up a base of readers, you do have to do some self-promotion, especially when you're just starting out. Steph has talked about how it's necessary on the One Direction fanfic site she's started posting on because there are so many stories being updated every day, it's easy to get lost in the shuffle unless you make an effort to draw readers to your story. That's not such a problem on AC, where stories may stay on the first Most Recent page for a few days, but I still tweet once when I update and post in my update thread here so people will know. I try not to spam everyone's Twitter timeline with tweets about my stories because I know not everyone reads them, wants to read them, or wants to hear about them all the time. If they do want to talk about them with me, awesome, but that's what reviews or the update threads here are for.
Obviously, published writers who are trying to make money off their books have to promote them if they want to make any money LOL. And unless they're self-publishing, there's a publishing company behind them that wants to make money too, so it's kind of an expectation! Most of us are not trying to make money at this, though; we're writing fanfic for the fun of it and posting it for free. We all want readers, but I must admit, I find it annoying when I see my timeline filled with lots of "OMG This chapter I wrote is so awesome; everyone should go read it right now!" tweets from the same person and people RTing compliments they received. I guess it's not much different from seeing lines from good reviews about a book on the back of the book's cover, but I think that's what makes it seem pretentious coming from fanfic writers. I don't mean to diminish what we do because I DO take my writing seriously, but I don't pretend to be the next Stephen King or something LOL. There's nothing wrong with talking about your stories; obviously, we all enjoy talking about our writing, or we wouldn't be doing it in this thread. I don't mind seeing people tweeting about what they're writing on Twitter. It's just when it verges on bragging that it becomes more of a turn off than an attractant.