Most active participants on XF have heard of them... And many sites actively utilize one or the other. Classic example is TAZ. A 69 page discussion thread over on XF indicates that it does have a strong interest. A 31 page support discussion node over on the Bob's official site indicates a fairly high interest and requests for assistance (I quit counting at 128 distinctive usernames). I had 3 copies myself that I used (still using one) and was not an active participant on his official support site - as are many others I am sure. A 24 page "closed" suggestion node indicates a fairly high interest - especially when you see that 80+ distinctive usernames have posted suggestions. There are still many add-ons that sites classify as "required" that have not been ported to XF 2. Until those are, most will remain on XF 1.x line. Not everybody found a need to rush like lemmings to simply upgrade to XF 2.0 because it was "the new Coke".