Karl Bunyan at K! Blog has gone one step beyond the rest of us & developed a piece of software that will add categories to blogger blogs. Behold Caterblogger. In return for the service, & along with your generated category listings, they'll place an adsense box on your blog.... but if that pays for the functions it might be OK.....

Karl had previously developed a solution for non-blogspot blogs using asp.net.

The solutions grow ever more elegant & sophisticated. How long 'til Blogger catch on & put us all out of business?