2002-12-31 21:21 UTC Why XBL?
Over the past few days, I've had the dubious privilege of defending XBL in www-style (archived). The person saying that XBL is redundant did not seem to fully comprehend what problem XBL was designed to solve, so I have had to carefully think about the issue. The result: a rather detailed explanation which addresses some aspects of the problem which I have not previously seen explained. (The juicy stuff is all above the horizontal line, in the first 35% of the e-mail.)
Hopefully it will answer some questions you may have about the technology.