Yeah, but these ads once again miss one of the biggest things- intent. At the end of the day, nothing you do on Facebook or Twitter speaks to intent. It's great for mindshare companies, like Dr. Pepper or Apple- but it just isn't very strong for local businesses, or more purpose-driven businesses like auto parts stores or coffee shops.
Not entirely true. At least in the Bay Area, I've seen some highly targeted ads on my Twitter stream. Twitter also does a great job at showing me ads based on who I follow. Do I act on these ads? Sometimes yes. Companies throw out incentives to act on promoted Tweets. I think it's a nice, subtle form of advertising that just works. Facebook, I don't like. Their advertising comes off very intrusive and honestly, I've never acted on a single ad there. Helps with brand recognition though. When I see a brand advertised on Facebook, I recollect it. How many times have you been to a coffee shop and seen posters redirecting you to their Facebook presence (I know that's not an ad but, it goes to show you that they have a presence there). Some take it to the next level and advertise too! I've seen quite a few local ads on my stream.