SODA 2011 will be in San Francisco. SIAM cannot on their own run a conference outside of North America, but needs a local organizer. We could not find anyone to host the conference in Paris proper. The best we could do was a suburban location, which I do not think would have counted as "Paris" even to the voters. So in the future, proposals for European locations will not be considered at Business Meetings unless they are made by people prepared to act as local organizers (as is done with STOC and FOCS).Just as well, I suppose. SOCG 2011 will be in Paris, in the Latin Quarter no less, and who needs to go to Paris twice in one year? And it's not like there are any algorithms researchers in Europe, anyway. (Well, except for all those computational geometers, but they have their own conference.)
All snarkiness aside, I am curious why SIAM is unable to organize conferences outside North America. I don't see anything about a North American restriction in SIAM's bylaws [pdf] or in their conference organization guidelines. (SIAM does offer more funds for invited speakers traveling from outside North America, which suggests an implicit assumption about location.) And while the majority of SIAM's membership is North American, they do have a significant presence in Europe and Asia as well [pdf; see slide 2].
More importantly, I hope this means that SODA will move toward a local organization model, like every other theory conference, instead of relying on SIAM he said comfortably from his corn-encrusted ivory tower deep in the snowy midwest.