Worry about Google, if the others happen then it's a bonus. If, and that's a big if, they truely become a player at some point then worry about making a few changes OR starting a site that is only optimized for Ask. But I don't think that will be anytime soon.
BTW, I am
#1 for my main term in Ask and have had Zero hits from them in the last 90 days. So they can claim to have traffic, but it is obvious to me that it isn't enough to care about.