Think of each category as a locationless of sorts -- the owner defines the target and the requirements for posting a waymark (as opposed to a find). The waymark is not exactly like a locationless find, because it can be posted by someone who hasn't necessarily visited it, depending on what the category requirements are. But in general they work much the same as reverse/locationless, and each location can only waymarked by one person within a category.
Then think of the resulting waymark as a virtual that can be found and logged as a visit by many. These visits have to meet logging requirements as well (which can be the same or different as the requirements for posting the waymark), but in all cases I've seen (so far) do require a visit to the location.
Finally someone has explained it in a way I can better understand. Thank you Bear Paughs! I am new to geocaching, just became a Premium Member, and Waymarking e-mail was the first to hit my inbox. I was becoming confused, and somewhat disgruntled, over many of the posts from people who are complaining about how it differs (or seems to) from the locationless and virtual caches on the geocaching site. Since I've never done either of these (though I did finally look at a couple that seemed they could be fun to do), I'm glad there is something in the works to expand my caching skills in the future. Also, being a military dependent, there are many places I have been, and hope to go in the future, that I could add as either categories or waymarks. The biggest thing I thank Bear Paughs for is stating that each waymark should be physically visited (if possible) and some type of "proof" should be required for a visitor to a waymark to log his visit. Some, I'm sure, will say that is not the point, but for competitions sake, that could be the "check and balance" that someone was saying might be missing. Instead of leaving it up to whomever makes up the category or waymark whether physical proof will be required, I say make it a standard rule for the entire site. Else even I could find coordinates for all the places I've visited in the past and have pictures for and never even leave my couch or computer. What's the fun in that? And, where's the health and wellness portion as well as the CITO that is so much a part of geocaching.