It's not completely accurate, but I think having a certain pagerank/alexa rating might be some sort of standard, if one is applied.
Would the same go for websites then, too? Because I notice there are some websites like Serebii.net, but then other popular ones like GTS+ aren't mentioned.
Also, this is an extremely minor detail, but on http://bulbapedia.bulbagarden.net/wiki/Great_Marsh#Items under Area 2, shouldn't it be "Hidden 3 trees WEST from the rock in the top corner" instead of "Hidden 3 trees from the rock in the top corner"? I say this because generally on that page (and others) the locations seem to be a bit more specific.
Also also, under Area 3, the Ultra Ball is "Hidden WEST of the train stop"