If you're building an online advertising business or one supported by advertising, the numbers released by eMarketer today--their forecast of online advertising spend over the next few years--might be of some help in deciding what kind of advertising spend to target.
Here are the subcategories and the compound annual growth rate of each category from 2006 through 2011, sorted by CAGR:
Rich media/video 35.6%Rich media/video advertising is pretty competitive, but there's not nearly as much energy being spent making lead gen a better business.
Lead generation 22.9%
Paid search 19.5%
Display ads 17.3%