In response to post #24608319. #24608409, #24608934, #24609194, #24609304 are all replies on the same post. It's a donation. It's a way for a modder to give back to the community that helped foster his work. Nexus isn't profiting off of this any more than if the modder in question just decided to donate a portion of his earnings to the site instead of having Valve do it on his behalf. Unless a modder requests it, the Nexus gets nothing. This is hardly a case of Valve's hand in the Nexus' wallet.