Books are good, because info is organized. I've read quite a lot of books, on multiple subjects related to it, and I will be reading more, now. One good book, that I've already read (just finished now, actually) is "Twitter for business" by Ted Prodromou. I had "Twitter for dummies" but this one was not very good, "Twitter marketing for dummies, could be better", but the latest edition is like five years old.
There may be a book or two, that I have missed, thats why I am asking. I would not be getting two more anyway, just one possibly, as I already read two. Twitter seems to be good, and also for adult. Good way of promoting a site, but it needs to be good. Not some rss feeed spun blog with low quality porn pics, and posting it to Twitter on auto pilot, this does not make sense.
There needs to be product, something that gets sold on a website, could be in adult niche, assuming people dont do it as a hobby, and want to make $$$. Then Twitter can be used for promotion. Find authentic people who can be potential customers, dont follow anybody (ie. spam accounts), reply, mention people (it will results in followers), add quality updates (dont just talk about anything, it is better to say nothing, than talk a lot of not needed things). Twitter can be good, I tested it, and it generated great results (good website - promotion on twitter, good quality -> this should work, better than Facebook, I would say).