Updated

A big part of Facebook’s announcement of its new location-based check-in service, Places, today was the list of partners who will be integrating with it. Those partners are supposed to illustrate the potential of Facebook Places as a platform; but showing off partners might also be a way for Facebook to say, “We come in peace,” and make clear that it doesn’t intend to crush location startups like Foursquare and Gowalla.

So executives from those two companies, along with review site Yelp and location startup Booyah, all took to the stage at the event to talk about how they’re working with Facebook. Yelp director of mobile, Eric Singley, and Gowalla founder and chief executive, Scott Raymond, both showed off ways their services will be integrating with Facebook. Gowalla, for example, said it will be better integrating Gowalla Passport Stamps, Photos, and comments within Facebook. Booyah chief executive Keith Lee unveiled a totally new app using Facebook Places called InCrowd, which adds gaming and social features on-top of Facebook check-ins.

And Foursquare … well, vice president of mobile and partnerships, Hogler Luedorf, (not cofounder Dennis Crowley, who All Things Digital had heard was coming) said the company is “looking forward to exploring how we’re going to leverage” Places. No real announcements, just a general endorsement of Facebook’s plans — including, yes, the common competitor’s remark that this is a great thing for “the still-small location check-in industry.”

So if you’re wondering what Places might mean for Foursquare, you’ll have to keep wondering.

Update: VentureBeat writer Cody Barbierri just interviewed Crowley about his take on Facebook Places and why Foursquare didn’t have anything to announce.