In Seymour Papert's (1980) seminal book Mindstorms, he is fascinated with the learning community of the Brazilian samba schools, and he discusses different ways for adopting the main attributes of the samba schools into more traditional schools. Two of the main attributes of samba school are "Learning is not separate from reality", and "Novice is not separated from expert and experts are also learning".
Since Facebook groups are accumulative by nature, new students register each year and graduates stay registered within that group. What happened unexpectedly was that students' questions were picked up and answered by several graduates who had the necessary expertise and who work within this field. In addition to answering questions, the graduates also posted new technologies, applications and tools, as well as some job offers.
Over and above the technical contribution by the graduates, their participation signaled to our students the relevance of their projects and of the technology they were learning. Although there are myriad ways to get technical help on the internet today, such as posting questions to stack overflow, the advantage of getting a graduate's answer is that he or she is well familiar with the student's background and skill set.
On the sociological level, this forum connected the students to a community with successful and skilled graduates, who spontaneously took the time and effort to give them a hand.
Personally, as the projects mentor and the Internet Development courses teacher, I have found that a great way to get updates on new application and tools in the field.