So this is about Twitter and not FB, but I went on a weird trip down the rabbit hole when looking into how certain accounts were becoming popular/growing so quickly.

There are a whole bunch of "networks" of fake accounts, often complete with very legitimate looking photos, names, and even posts. The main difference, however, is they follow and retweet a lot.

If you look at what they follow and retweet, however, well over half seems to be "legit" stuff that wouldn't be getting involved in such schemes. I think the reason is that if Twitter decides to crack down on bot networks, they might look at what the bots are following and promoting to work out who to penalize.. except they aren't going to start deleting CNN, Fox News or random celebrities.. so they really have no great way to tell who to punish. I suspect FB bots work in a similar way.

Not the legitimacy of the page being liked, of the bot's profile. Filling it with dummy information, including various liked pages, posts, etc, to use them for astroturfing.

People follow pages and join groups and all that, so bots have to do that as well to blend in. It's to make the bot more legitimate.

I'm not sure they're bots, rather people cheaply paid to create fake accounts, or scammers. I've seen many of them, and some of them are quite amateurish. They would say they went to Florida University and come from Florida City, working in... oil.