WHERE IT'S AT:
When Beck first emerged, he was a novelty: the "Loser" guy. The more discriminating listener was aware of Mellow Gold's more interesting tracks, like "Truckdriving Neighbors Downstairs," but the sum total of all this made him, perhaps, someone to keep track of for the future. Rock magazines would repeat that he had a special deal with Geffen (I think that was his label) which allowed him to write and record more experimental music for independent labels, but this was the early-mid 90s, which meant no one had actually ever heard it.
Odelay! was different, the sort of thing that happened with happy frequency in the 90s: a critically acclaimed album that was also popular. (To the best of my recollection, the only time these two ever collided in the Aughts was "Hey Ya!") It was generally assumed that Beck represented a sort of alternative future for rap music, something different than gangsta rap and its glorification of the women-and-money aesthetic. Rap music, in other words, you didn't have to feel guilty for liking.
The tip-off that this was something different should have come in the liner notes. Sampling a piece of a different song to include in yours had been a widespread practice in the late 80s and early 90s. The practice was in murky legal waters: it was not particularly clear whether a sample required a royalty payment, or even acknowledgment. One could even argue, reasonably, that a small sample constituted a form of fair use--the link I posted a few weeks ago to the youtube video on the "Amen Break" is a good example of this. Nevertheless, by the mid-90s the legal issues had been cleared up, and all samples had to be cleared and acknowledged. The liner notes for Odelay! contain a page or two (in tiny type) listing all the samples used on the songs.
Beck's departure was radical: rather than a song built off one sample, or borrowing from a sample for a hook, the songs were composed, embellished, and built up on the basis of bits and pieces borrowed from other people. It was, in other words, not the latest expansion on rap, but the first genuinely popular electronic music.
(It worked, of course, because Beck has genuine songwriting and compositional chops of his own, as he would go on to demonstrate over his career)