If this week’s Where 2.0 conference is proof of anything, it’s that developers are excited about creating location aware mobile apps. One of the biggest barriers to creating a place-aware app, however, is getting the ball rolling – you need place data.

Place and location, though hand-in-hand, are two different things and SimpleGeo, a geolocation data storage and platform service, announced this week that it has put data for more than 20 million places into the public domain to make it easier than ever for developers to create location-aware applications.

“It is our belief that facts should be free, as in freedom,” SimpleGeo co-founder Matt Galligan wrote yesterday on the company’s blog. “We wanted to see the proliferation of places data that developers could easily use, reuse, or basically do whatever they wanted with, so we took matters into our own hands and began building our own database of places that were free of the existing restrictions in the market.”

When it comes to location, an app can use any number of signals, from triangulating with WiFi signals to using the in-phone GPS, to determine the device’s exact coordinates. But coordinates are just numbers that relate to a point on a map. When we check in to a place on Foursquare, we don’t check in to GPS coordinates, we check in to the coffee shop or the baseball stadium. How does Foursquare do this? It takes our coordinates and relates them to place data. Place data can involve a number of different data points, but at its most simple level, place data attaches a name to geographic coordinates. It can go well beyond that, however, including coordinates to define a place’s shape and size, the zip code, the city, state and county that place is located within, and so on.

With this week’s announcement, SimpleGeo is saying that the data for nearly 20 million places that it owns are now available, to use freely, under the Creative Commons Zero, or “No Copyright,” license.

“Developers want to do a multitude of different things with data,” explained Galligan. “There is a future we want to get to when facts are free. We’re trying to force that hand a bit.”

Galligan acknowledged that some of this data, which is often crowdsourced from multiple sources a la OpenStreetMaps, isn’t as good as propriety data quite yet, but it’s on its way.

Joe Francia, editor in chief of Directions Media, acknowledged the effect this move could have, but also looked to data quality as the primary weakness.

“Certainly, ‘free data’ under CC0 shakes up the business model of those who for years have invested in collecting data under a proprietary (read expensive) model,” said Francia. “What remains to be seen is if their own sourced data can be maintained and updated in a timely manner. People want good data, regardless.”

Nonetheless, a 20-million-strong set of place data could be a great jumping off point for any developer who wants to get into creating place-aware applications without being beholden to the terms of service of companies like Facebook or Foursquare. Galligan encourages developers in his blog post to “take our data, use it, make it your own, and make it better.”

Today, he told us simply, that “the developer needs to have the freedom to do whatever the heck they want.”