i have to agree with . . . because yahoo answers hasnt changed FOR QUITE SOME TIME . . . maybe even the early 90's LOL (Gallito)
Web 2.0 Background it is and i think its under open source license, anyone can use it. i have seen tons of sites using this one.
It is not the same background. Check it: Aol background:http://o.aolcdn.com/art/dynanews/background-tile Yahoo abckground:http://l.yimg.com/a/i/us/sch/gr/bggreydiag.gif