Thomas:
There are many, many rankings of golf courses around the world. For example, there are a couple of competing golf magazines in New Zealand, each with their own list. Same for Australia. In the bigger countries, these magazines are often affiliated with the major U.S. golf publications, and they may send their own local rankings up the chain of command for consideration; I think there is at least some hint of tokenism like that in the GOLF DIGEST international rankings.
Likewise there are many U.S. states with publications that purport to do rankings of the best courses in those states. Some of them have panels of golfers to do the rankings -- though many of them would be local pros or top-flight amateurs with pre-existing knowledge of the courses, so they don't add much to the numbers of people turning up at the pro shop as "raters." Other publications keep it mostly in-house among the editors, and may be affected by advertising considerations. GOLFWEEK in the old days used to let subscribers vote, and for years the Bloomingdale Golfers Club was rated #1 in Florida, ahead of Seminole etc. [I'm pretty sure they stuffed the ballot box.] The Dallas Morning News has (or had) rankings for the best courses in Texas, but I don't know of too many other rankings by big papers like that.
As you get further afield to Europe and Asia, most countries are small golf markets, and rankings are more easily bought off. Even the big international rankings are prone to "errors" on courses in Asia, because the owners are willing to spend a lot of money for the prestige of being included, and only a small subset of the panelists get to those places ... so it is very easy to ply them [and/or the editors] with special treatment. It would be hard to do the same thing for courses that are more accessible to panelists at large, so it is less likely to happen for U.S. courses, although some of the ultra-private courses use their complete control over who gets to play to cherry-pick the guys they give access to.
There are more than 1000 panelists for GOLF DIGEST and another 500 for GOLFWEEK and another 150 for GOLF Magazine, each playing and rating an average of 40 courses a year. If we assume they're all playing the same 1,000 courses, then each of those courses would be hosting about 65 panelists per year; but if we assume that some of the better courses get more requests, that means they might see 150 requests for access per year.
Those are roughly the numbers for U.S. courses. Elsewhere around the world, I would expect the numbers to be significantly smaller. Hypothetically, if you owned a course in South-east Asia and wanted it considered for a top 100 list, you would only have to spring for 10 people to come and play it over the course of 2-3 years ... some of whom might even pay their own way. Or, you could fork over $2 million to host some sort of "prestige" event. Hosting tournaments was the way it was done back in the old days, before clubs figured out that hosting panelists was a lot less expensive.
I do like the "top100golfcourses" web site as a starting point, as Jeff mentioned. Based on my experience in the Canary Islands last year, its rankings may also be influenced by outside factors -- the highest-rated course there was the worst one of the four I saw -- but as with all of these things, it's all subjective and "buyer beware" !
Unfortunately, that's the cover under which some real b.s. happens in this world we live in.