said 1 year, 3 months ago:
Facebook is no longer penalizing third party publishing apps (see http://www.allfacebook.com/facebook-pages-publishing-2011-11). We have made several tests recently and the reach of a post published directly on the wall or throug a third party app (ours was the same.
For your understanding, there are service, such as hootsuite, which use the same publishing app for their millions of users, which is more risky for the edgrank, and others, such as Buddy Media, Vitrue or agorapulse, that use a dedicated app for each customer, so no adverse effect on the edgerank…
And yes, Facebook is a complex environment