I think its way more likely that if/when twitter launches a location product similar to foursquare that /that/ will do them in. Facebook is for a different type

I think its way more likely that if/when twitter launches a location product similar to foursquare that /that/ will do them in. Facebook is for a different type of relationship (at least to me) whereas 4sq/twitter is more selective- Who do I want to follow. I feel that twitter could completely replace 4sq, as their is nearly 100% overlap in that space anyways.