Playing tag with the unwitting

Spend on behavioral targeting will increase to $4.4 billion by 2012, up from $775 million this year, with online video a major driver of that growth, according to eMarketer (via MarketingCharts).

Growth in the next couple of years is expected to gradually increase (to 1.7 billion in 2010), then jump significantly in 2011 (to $2.7 billion) and again in 2012:

One of the biggest drivers of behavioral targeting growth over the next four years will be online video, which is growing at a snappy pace, although ads placed around video are high-priced, eMarketer said.

As more video becomes available online, advertisers will use behavioral to target those ads and make their media buys cost-effective, according to the firm.

It accordingly forecasts that in 2012 behavioral targeting will constitute nearly 24 percent of the display ad pie, which includes video - despite accounting for just 8.6 percent of total online ad spending:

Among the current obstacles to the growth of behavioral targeting, eMarketer said, is that marketers are put off by how the technique can serve ads at any time on any site, without consideration of context. They worry, therefore, that their ads will show up in an inappropriate spot.

Marketers also fret that segments of consumers may be targeted too well - making targeted groups that are too small for sufficient reach. They are also cautious about infringing on consumer privacy.

Because of privacy advocate concerns, the Federal Trade Commission decided to hold hearings on behavioral targeting.