Matt Galligan, co-founder and most recently Chief Strategy Officer of SimpleGeo, the geodata platform provider we've written about here many times and named the Most Promising Startup of 2011, just announced on the company blog that as of today he's no longer a SimpleGeo employee.

SimpleGeo is aiming to be one of the most important companies online in a future where the Internet is not about placelessness - but where online content and knowledge are available on demand to mobile app developers and their users.

Galligan and CTO Joe Stump founded SimpleGeo in the Spring of 2009, the company originally intended to be a mobile gaming augmented reality service (it was originally known as Crash Corp) but pivoted to become one of the leading providers online of data about geographic places and landmarks. Galligan was CEO until last November when he stepped aside to make room for the newly hired Jay Adelson, who was best known of late as the CEO of Digg but who had been far more successful elsewhere, in leading multiple billion dollar companies in the data and enterprise markets.

Galligan says he will continue to advise Adelson, Stump and the rest of the team.

Prior to co-founding SimpleGeo, Galligan co-founded a social media user activity data aggregation service called SocialThing, which AOL acquired in hopes that it would help it challenge the social technology Facebook built and used to so dominate the web.

Galligan hasn't announced what he's doing next yet. The only other current work listed on his LinkedIn profile is advising of an unlaunched startup called Veri, which seeks to combine collected knowledge and multiple-choice quizes to build "personalized learning paths" for each of its users.

Update: M.G. Siegler was more successful in reaching Galligan than I was this afternoon and found that Galligan's next plans are to help leading tech incubator TechStars and a new nonprofit called 1% of Nothing. That efforts encourages tech startups to commit equity to charities in case they have a meaningful exit later.