I call these "feel good threads", a Search Engine Watch Forums thread talks about the advancements Google has made in online advertising.
Starting from the classic simple text based ads triggered by keywords in search results to AdSense contextual ads, to image ads, to video ads, to CPM vs. CPC to CPA ads.
Let's not forget audio ads, print ads and soon to be TV ads. What has worked best so far? The original keyword triggered search ads.
The thread creator put it a different way:
1) Ad formats You've got text, image and video. Text rules. It's the workhorse of ad formats.
2) Ad distribution You've got keyword targeted (on the Search, Content, and Mobile networks), and site targeted. Keyword targeted blows site targeted away.
3) Payment methods You've got CPC, CPM and CPA. Without a doubt CPC totally dominates. CPC revenue has single-handedly built Google.
AdWordsRep loves the thread, and moderator, KevinSource, said:
Agreed! I have been using AdWords since August 2002 and the products that were first available are still the best performers...Keyword Targeted, CPC Ads!
Forum discussion at Search Engine Watch Forums.