Why is this surprising?
No one builds a jingle or a slogan or even a brand identity using web advertising. It's never been done to my knowledge and it's hard to see how it could be done.
The purpose of web advertising is to get interested people to raise their hand and give you permission to have an anticipated, personal and relevant conversation.
The web site and the blogs and the interactive email conversations and the petitions and the online buzz are where minds get made up and where ideas spread. Not in the Adwords.
Did either campaign do a good job in building an online asset of people who actually want to hear from them? Nope. Moveon did, definitely. Everyone could have done far far better, but political operatives are impatient and greedy and forget to build an asset for when it really matters.