For many years, Disqus has been the gold standard commenting system for web sites, thanks to its ease of use and integration with many social networks. Its temptations have been especially hard to resist for web sites using static content generators, a growing trend with many appealing advantages. But it's a solution with several problems, both for the owner of a site and its visitors.
If you've used any graphics program that specializes in landscape generation, such as Terragen, you have probably seen that a core feature is the ability to automatically calculate the borders between snow, barren stone and grass from the geometry. Snow is only possible above a certain altitude where the temperature is below the freezing point, and even there snow will not stick on surfaces that slope too steeply. Similarly, grass will only be found below a certain altitude where it's warm enough, and will also not grow on too steeply sloping ground.