Well, I don't particularly like the idea of Search Engine Optimization, because it seems worrisome and somehow vaguely wrong to tempt the Anger of The Great And Powerful Glorious Google.
However, since Mcain himself has hilariously decided to troll the internet himself - for omg ponies points!!! I think the Searching for John McCain project is fair game and a great idea.
But it's forgetting one potentially powerful strategy, in my humble opinion. Misspellings. I believe the current president calls them "mispellifications."
The Searching For John McCain project states as its purpose the targeting of curious, low information voters. Sure, at this point we all know how to spell John McCain, but we're all obsessed - besides, admit to yourself that you were still spelling the all-but-presumptive Democratic nominee's first name "Barak" as late as Super Tuesday (maybe that was just me). What if you've only heard the name on the radio? What if you've never typed it yourself?
In yet another internet technique pioneered by the porn industry (ever been to whitehouse.anything-besides-gov?), it's a smart idea to target common variations misspellings, both in domain names and in search engine optimization. When dealing with search terms, there's the added benefit that it's way easier to google-alter the less common term.
Luckily, Google gives guidance as to how to target a Searching For Misspelled John McCain effort. The following chart (the link to Google Trends' analysis is here) ranks the real and mistaken misspellings in order of most to least popular.
Other variants, like Jon Mcain, don't register at all; clearly Mcain and John Mcain are the best bets, unless other people can suggest better variants.
[Update] At drdave's suggestion, here are three cut-and-paste "mcain" links for Searching for John McCain-targeted pages.
<http://www.salon.com/politics/war_room/2008/05/22/gi_bill/index.html">mcain</a>
<http://www.msnbc.msn.com/id/24844889">mcain</a>
<http://articles.latimes.com/2008/mar/01/nation/na-mccain1">mcain</a>