Didn't someone patent the technique Carmack invented or something?
Creative patented "Carmack's Reverse". He didn't really invent it, but figured out that if you where generating your shadow volumes backwards, you got a more realistic result. Read more.But to answer the original question, I don't think it's fair to call stencil buffer shadows a "fad". Certainly not by my definition of the word.
Cascaded Shadow Maps on the3 other hand, now there's a fad... :o>