(Dean looks around Rory’s bedroom, and picks up a CD)
DEAN: Wow. Very clean. How much does it suck that they use Pink Moon in a Volkswagen commercial?
Dean is referring to the song Pink Moon by Nick Drake, earlier identified as one his favourite singers.
This is by far the most pretentious and hypocritical thing the usually down-to-earth Dean ever says in Gilmore Girls. Nick Drake had been obscure for decades when his song Pink Moon was used in a Volkswagen commercial. Without the commercial, Dean would never have even heard of Nick Drake, and as the commercial only came out in December 1999, he had been a Nick Drake fan for less than a year.
I can only imagine he was trying to impress Rory with his hipness, by making out that he had somehow known about Nick Drake previous to the commercial, to the point where he could feel betrayed that they used his music to sell Volkswagen. I’m not buying it.
In turn, Rory clearly went out and bought the Pink Moon album just because Dean liked it, then pretends that she knows and cares all about it to the same extent. But the show lets us know that, whereas that isn’t the case with Dean’s statement.