Ok, I admit it, I googled for top paying AdSense keywords. What did I get? Well, I suppose, pretty much the same, everyone else also gets, when looking for this. A long list of phrases containing all kinds of combinations of financial keywords like "debt consolidation", "credit card report", "mortgage refinance rate" and so on, all garnished with an unrealistically high dollar price tag.
Who compiled that list? Nobody knows. How was it compiled? Not stated. Is the price tag what publishers are suppose to earn or what advertisers are willing to pay? No clue. When was the list compiled? No info. Curiously and despite lacking any credibility, that list seems to get copied from blog to blog and from forum to forum, usually being brutally butchered and modified in the process.
What really irks me about the various incarnations of this list is, that localized phrases are apparently highly profitable. This seems totally odd to me. I mean, why should student loan consolidation in Alaska pay some 60+ dollars? Think about it, how much competition can there be for such a highly specific phrase? My estimate is pretty much: none. A phrase with little competition should actually result in a low payout, except of course, when the advertiser in question was totally clueless in setting up the campaign (a state, that is guaranteed not to last very long). I have this funny suspicion though, that this was not entirely the case.
Time for some quick tests. Let's pick a couple of those insanely specific phrases and just throw them into Google search. If they really were that lucrative, than there should be some fierce competition for them and Google would probably jump on the opportunity to garnish the search result pages with some ads, of their own (after all, that is what AdSense was originally spun off, right?). All I seem to get though, are websites and blogs which appear to target these specific keyword combinations.
I wonder... Could it be, that some clever entrepreneurs came up with the original list? Compiling so specific phrases, that they could be sure, nobody else would campaign for them, and then "leak" this list, pretending it contains phrases so lucrative, that you just have to target them? I mean, sounds like a plan, doesn't it? Instead of investing a lot of time and money into marketing yourself, just tell those who are interested in making money fast from home, that your keywords pay handsomely, then wait for them to build whole blogs around them, let them do the pesky link building and when they are finally able to actually send some visitors your way, just pay peanuts.
Update: After doing some more research on the topic, I have to amend my position here. It seems like the implied lists were compiled by using AdWord's own bid suggestion tool, which in fact spits out ridiculously high price tags for some keywords/phrases (especially long and highly specific ones). These numbers are however only suggestions for what an advertiser should consider to pay in order to ensure to get hold of one of the top three slots. Naturally, this is not what advertisers will actually pay and most certainly not what publishers will get for a click. On one hand, the algorithm, making these suggestions seems to be skewed (the more keywords, a phrase consists of, the higher it's price tag), on the other, there is simply no need to be always on top.
Whoever compiled these lists of high paying keywords obviously did a hack job at it, simply feeding the AdWords suggestion tool with some keyword ideas and then excerpting those phrases with the highest numbers without bothering to check, whether or not there is actually any competition for them (this could have easily been done by typing them into Google search and see what banners Google runs on it's own page).
In conclusion, I was (probably) wrong about the motivation for compiling those lists. It's far more likely, that they are just the result of bloggers trying to attract more visitors. The lists are still useless though. Building a blog around them in the hope of getting rich is a vain attempt.