Well, that feature is now out in the open. You can see the brown bar on the site that says:
To learn more about it, click on "About This".CactiGuide.com Custom Nomenclature - System Default About This | Login
It won't be immediately apparent what this is and I expect it to take some time to catch on. We are quite used to the static nature of printed books and catalogs that we often don't think of things dynamically.
As of today, CactiGuide.com no longer follows Anderson's classification system, although, Anderson's system is still fully represented here on the site and soon the classification used in "The New Cactus Lexicon" will also be available (as of now, it is up to Gymnocalycium). I plan on also including Backeberg, Britton & Rose and smaller publications as well. And hopefully the input of individuals who are well studied, but may not have a published work.
These systems are available to be viewed on their own or in comparison to other systems.
I hope this system proves a valuable resource tool for everyone. It is just a beginning, but there is much potential - I look forward to us all having an increased understanding of cacti taxonomy as a result!