As someone who has used Facebook in multiple classes in the past, I found that the findings in the Manca and Ranieri (2013) article were largely in keeping with my own, more casual observations. I've created Facebook groups for 4-5 of the lower-division courses I've taught, and I have mixed feelings about these groups.
On the one hand, I really liked how I was able to quickly relay information to my students: I would send an email, then copy/paste it into a status update in the group, and I could see at a glance who and how many people had seen it. Given that some students are still not in the habit of regularly checking their university email accounts, this was usually a very effective way of communicating with them. I also liked the ease with which new materials, such as videos, pictures, links, etc., could be added and commented on, and whenever multiple students "liked" a particular resource, it let me know that they found it useful (or at least amusing/interesting enough to acknowledge--I'll take it!).
On the other hand, I was essentially giving students access to me via a more personal side of my life. Granted, my profile picture is professional and my profile is set to private, but still: they knew "where" I was on Facebook, and I knew "where" they were. Also, there was generally very little interaction in the groups: although I made it clear to students that they were welcome to post relevant resources/initiate discussions, this was rarely done, and most students seemed to regard the page as a sort of "resource feed" that they would check prior to exams.
Given that more and more of my students are telling me that they don't really use Facebook (honestly, neither do I: like them, I mainly skim through it to keep up with family), I've stopped creating Facebook groups, and I haven't had any complaints. I'm familiar with and regularly use other online platforms--Tumblr, Pinterest, Instagram, etc.--but so far, I haven't had enough students in a single class who were also users of a site to warrant the creation of a class page (although Instagram seems to be gaining steam).
What about you guys? Have you ever used, or do you currently use, Facebook groups in your classes? Do you have other online platforms that you use or that you would like to use in the future?