Advertisers continue to invest heavily in online advertising, despite teething troubles in the Internet economy. However, most of this money is captured by a handful of top websites, so many websites offering advertising space are finding it difficult to survive solely on advertising income. Compared to offline advertising, it is relatively easy to measure how many people view or receive an advertisement displayed, say, at a website or sent in an email. Originally touted as the great advantage of online advertising, this measurability has become something of a millstone. Only recently have people begun to judge online advertising more fairly, and also realize that it's often the message, and not the medium, that is the problem.
Many Internet users have an ambivalent attitude to online advertising.
With many advertisers tracking the actions of those who view their advertisements, there have also been concerns about privacy.