Will Burns is CEO of Ideasicle and also Forbes' key contributor on advertising. In this article, he discovers liking an ad does make one feel better about the advertiser (Reputation), but doesn't necessarily produce Actions such as Purchase, Recommend, Buzz, Contact, etc. Thus, just measuring likeability isn't enough; you've got to measure other KPIs to establish true creative effectiveness. Today, you can do this better, faster and cheaper through syndicated testing from folks like ABX. More details on these KPIs are available here.