Putts, especially the long ones, are noticeably affected by winds in the CTTH's where one has the opportunity to try them over-and-over again. But it's hard to say whether the roll is affected more while the ball is traveling upslope, or down.
It's relatively hard to evaluate just how much they are affected in stroke-play, as slight variables (ball placement, elevation, slope, etc.) that enter the picture can account for differences in those putts' roll-paths and lengths. Being able to replicate "exactly" - a putt on a flat green, with varying windage - would surely be invaluable in ascertaining just how much affect the wind truly has, but I've not come up against a "flat putt" in a CTTH challenge, as yet.
Noticing this in the CTTH's, I usually "play it safe" in stroke-play, and assume a "very slight - with the wind" affect when attempting to hole putts over 20 feet.
Excellent link, Casper. :)