This point deserves an additional comment.
The three behemoths of online advertising at this moment are Google, Facebook and Amazon (who is well behind the first two).
- Google knows what you want (via search queries / Google Analytics)
- Amazon knows what products you're interested in and what you want to buy (based on product search / purchase history)
- Facebook knows who you are (based on likes / analytics from Facebook like buttons all over the Internet).
Broadly, Facebook has some of the most effective audience based targeting ever invented. But
@se900se point still rings true. Let's use
@on1 's insurance example. There are certain websites made specifically for people that are looking for information about insurance or insurance products. Or people that are looking to become insurance brokers or something like that. A well-placed banner or native ad on one of these sites is often more effective than Facebook's audience targeting because when the user is on that website, they are specifically looking for information about insurance. Meaning they are especially receptive from an advertiser with authority, and said advertiser has the authority because they're running ads on that site!
Obviously the ad copy of the banner and landing page post-click need to look legitimate as well, but ad network buying can oftentimes be better than buying Facebook ads. And not everyone knows that.
PerimeterX, Dstil Networks and Encapsula are some companies that will filter bot traffic. They will ID a visitor coming to a page and if the visitor is a bot, they will serve the bot a broken page. One could feasibly build this themselves using the most common bot behaviors listed in my earlier comment. I've done it and it works decently well to keep easily ID'ed bots off a site.