The Search Engine Marketing Professional Organiztion (SEMPO) found in its 2008 State of the Market survey that advertisers and agencies are embracing new marketing platforms and "showing an increasing willingness to pay more for targeted reach through behavioral targeting and local search."
What is typically most interesting in studies of this nature (at least to me) is how much more advertisers are willing to pay for a specific type of targeting or marketing feature, as it offers some good insights into how much an industry is already saturated and how much room it has to grow. In this case of this survey:
The use of social media was also a focus of the study. Among advertisers doing social media marketing, more than four out of five are using Facebook to promote their brand. Digg is the second most popular social media site, with more than two-thirds of advertisers using it. Del.icio.us, StumbleUpon, Reddit and Technorati round out the most popular sites to promote brands.