I was just thinking about the albums from the aughties that were sleeper hits, or built steam over the course of the decade. Albums that were the opposite of "Is This It." The first one that comes to mind is The Shins' "Oh Inverted World", but I'd say that "Funeral" built quite a bit of steam over the course of the decade too.
I think Boys And Girls Of America's increase from 2006 is due to it's delayed release in the UK.
Speaking of the opposite of which, Amy Winehouse - Back To Black. It had it's initial mainstream bump with the success of rehab, then the mainstream attention faded and the album built up more critical steam.
XTRMNTR, Demon Days, The Glow Pt 2, Damien Rice - O are more albums that I think are better known now than they were when they came out.
Regarding the Pitchfork effect, I think it only sticks around in the cases where it is justified. For instance, The Rapture - Echoes got a big bump when Pitchfork made it their #1 of 2003, but people aren't talking about it much now.
The one that sticks out to me is Yo La Tengo's And Then Nothing Turned Itself Inside-Out.
The sucker even made Rolling Stones' top 100 of the 00s.
And given that it came out in 2000, it had plenty of time to be forgotten.
I'm glad it's getting respect, it's a great album. It's a very subdued and "mature" album per se, so it doesn't have the qualities that make for an instant classic.