Several people have replied (some have taken ModPo, some haven't) and I thought I would add my own experience to theirs. My response can be found below, although I highly suggest you read the article in question first as well as the other well thought out responses.
I'm a MOOC taker and proud of it! So far I've completed one course on Coursera and am currently taking two others - one on Coursera and the other on Udacity - in addition to taking a for credit distance learning course in Game Development. Am I learning? Yes, very much so! Do MOOCs create a community? Again yes!
With ModPo we had the forums - which were always busy, several Facebook groups, study groups - some online via email or Skype and some which met in person, a twitter list and hashtag, in addition to the live webcasts where we could phone in and talk with Al and his TAs. The other Coursera course that I'm taking also has a good sense of community in that the more experienced students are in the forums and the Facebook group helping out those of us who are new to the subject as well as people being engaged in general conversations pertaining to the subject in both places as well.
I've actually experienced more interaction with the professors and other students in the MOOC setting than I did when I attended a physical college! So yes, there is most definitely learning occurring within the MOOC structure!
In addition to all of this, taking my first MOOC has resulted in something which I thought was lost - a love for poetry and an interest in writing. During the ModPo course, several of the modern poets we were studying interacted in the forums with the students. As a direct result of this I took on a challenge from Kenneth Goldsmith himself to write a "sequel" to his book "Soliloquy" - something which I would have NEVER thought of doing had I not taken ModPo. I start writing my book on the 21st of December and hope to have it available, in digital format, sometime in January 2013.