I've been half-jokingly entertaining the idea of trying to blog about "n ways not to solve P vs NP" in the indefinite future, and in my search came across the How not to solve P=NP? question on cs.stackoverflow.
Clearly P vs NP is a great starting point, being the source of so much development in TCS. But this got me wondering if there are other problems where people have consistently published their failures, or just any thoughts on why some things don't work. Surely not in papers, unless a strong negative result came out, but probably in blog format (which is increasingly becoming its own medium for communicating science).
Of course, this doesn't seem very practical (unless you store all your progress in digital or easily-convertible-to-digital format), but maybe the benefits outweigh the costs. So the other natural question is, how useful do you think it would be if we started doing it as a community? How often is a failed attemp one (or several) steps away from a success?