When I referred to general information, what I meant was aggregated information. When we show advertisements to large groups of users, we may tell the advertiser general information about the people in that group. For example, we might say this advertisement was shown to 100,000 people, or we might say 50% of the people who saw your advertisement told us they were male. We're not providing information that is specific to an individual, just information that will give an advertiser a sense of the population they are addressing. That's what I meant by general information.
We don't have a specific list of all of the advertisers on Facebook, because that set of companies is constantly changing. The information they receive is not individually identifiable to users. When there are advertisements that appear on Facebook, there's an “x” that appears next to each ad. You can click “about this ad” to learn about Facebook advertising generally. There's also an indication there in most cases of the identity of that specific advertiser.