AdweekMedia/Harris Poll conducted a survey to find out what kind of advertising people were most likely to ignore. And a majority of the vote goes to Internet banner ads. 43% of those surveyed stated that Internet banner ads were the advertising type they ignored the most. Internet search-engine ads also did poorly- 20% claiming they ignored them the most. So why is it that these types of ads are most likely to be skipped over and disregarded when they show a great amount of individual connection.

As far as Facebook goes, it seems to me that people have no desire to follow a banner ad because that is not what they're on Facebook for. They are looking for a connection to their peers and family and not for an advertisement that they are bombarded with constantly. In addition, these banner ads have become almost ubiquitous across the Internet; so much so that I can't recall the last one I noticed simply because I ignore them all. It could be that the amount of these ads is overwhelming and the actual importance of them is minimal. They have simply become background, part of the landscaping that comprises the Internet. They are just a piece of the structure that, more or less, has very little importance or influence over our daily lives.
http://www.adweek.com/aw/content_display/news/digital/e3iff352c323b9a2c10626c155c7736411a