For some reason I don't understand I've been willing to share my location, at least sometimes, on Facebook. I haven't been willing to do so on Foursquare. I'm trying to understand the difference. 
Maybe it's like listening to a song on the radio, vs playing it for yourself. Or watching a recorded sporting event vs watching it live, even when you don't know the outcome. It's a shared thing. There are so many more people on Facebook, but more important, I have a feel for who they are. Foursquare is much more of an unknown to me. 
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By building up a database of places, we're creating a resource for all of us. But, that's not really what we're doing. We're creating intellectual property for Facebook's shareholders. 
And that sucks. I've been snookered into being part of a crowd-sourcing business model. I'd much rather be part of a Wikipedia-like business model for places. 
Maybe it's not too late to get into competition with Facebook on this, after all, they just started their places database in the last few weeks. 
Where is Twitter's places database? Will they not get into this area because Foursquare is already there, and Union Square/Spark are already invested in Foursquare? I wouldn't wait if I were them. Maybe the two companies should merge. 
The lead Facebook is building now will seem very large very soon, it seems to me. 
But the rest of us, we're not co-owners in either of these portfolios. 
Can we, should we be focusing our efforts on building a database outside these tech companies? (I don't know if we can but I do know that we should at least try.) 
I'm sure there are open source projects to do this. The key thing is to have a user interface as easy as Facebook's. Or even better, a commitment from Facebook to share and freely license the places database they are building. That would be a great way to nail this thing down, now. 