A/B testing is the comparison of two products by providing each, simultaneously, to two randomly selected groups. As Michelle Meyer notes, the practice is less ethically suspect than a common alternative: imposing a new product on all of one’s customers without first testing it.
A&B is an abbreviation for assault and battery. Depending on the jurisdiction, the two may be a single crime or distinct crimes, but everywhere A&B is unlawful.
Law professor James Grimmelmann has confused the two:
Suppose that Professor Cranium at Stonewall University wants to find out whether people bleed when hit in the head with bricks, but doesn’t want to bother with the pesky IRB and its concern for “safety” and “ethics.” So Cranium calls up a friend at Brickbook, which actually throws the bricks at people, and the two of them write a paper together describing the results. Professor Cranium has successfully laundered his research through Brickbook, cutting his own IRB out of the loop. This, I submit, is Not Good.
IRBs for everyone, or you get hit with a brick. I suggest that this parade of horribles is missing its elephant. Blame the IACUC?
Anyway, thanks for the link.
ETA(2:18PM): I originally linked to the wrong Meyer paper. Of course, that one's worth reading too.