Sure. But whatever Mahalo's done, they haven't made it seem like they wrote the questions themselves. The visual design attributes the questions to the 'fluther' Twitter account (and link to the exact origin Tweet).
Are you angry they're making questions by your users seem like they were written by Fluther itself? That seems a legitimate concern, but your own Twitter stream similarly blurs question authorship.
Are you angry that they synthesized a 'fluther' account on Mahalo and thus made it look a little like you're endorsing Mahalo with your participation? That's what I would be most angry about, if my question-tweets were showing up, under my unique username, at a site I'd never opted into. But one remedy for that concern might then be to remove attribution -- making the questions from 'an unnamed Twitter user'.
