Facebook is going back to its college roots today, adding new groups features available specifically to college students to aid in collaboration and sharing. Facebook Groups for Schools is expanding to more schools with a couple of new features in tow: file sharing and a very slightly relaxed set of rules for students who attend the same university.

Facebook Groups for Schools is an extension of the currently existing Facebook Groups feature, but with a special emphasis on schools that includes both school-specific workflows for new users and the ability to include and invite anybody with the appropriate .edu email address. The program has actually been in testing at various schools around the US since December, notably Vanderbilt and Brown, but Facebook is beginning what will be a weekly expansion to new schools. The purpose of the groups is to help students (and faculty) connect with each other other in a cozier and more private environment. Although anybody can see the names of the groups and who is a member, only actual university members can view or participate in the content.

"College is a natural place for groups." We spoke with Facebook's Todd Jackson and Raymond Endres about the new feature, who laid out the motivations and design challenges behind the new feature. At its core it's about making it easier to form smaller sub-communities within the gigantic monster that is Facebook. The net effect is to make Facebook feel a bit more like it did in the very early days when it was only available to college students. In getting to the current version of Groups for Schools, Facebook iterated through at least ten different major versions — and it intends to continue iterating as the product spreads to new schools.

In addition to the new schools, Facebook said that the two most-requested features for groups during the testing phase are getting added. The first is file sharing for collaborating around school documents. The second is "better" messaging, which allows students within a school to message anybody at that school. If you're a participant in Facebook Groups for Schools, the contact field will auto-complete to anybody in the school and you do not need to be friends to message other people with the same .edu domain — though of course Facebook still respects the privacy settings any particular member sets for allowing contact.

Facebook tells us that it has found great success piloting new features to college students, who are more likely to try out new functionality and more willing to share feedback quickly. Much of how the new Groups offering looks today is a direct result of that feedback. Facebook has spent time crafting ways to maximize both comfort and participation among new users.

"We're essentially crowdsourcing the creation of all the right groups in a school."The sign-up page for Groups for Schools offers a simple questionnaire that is less intimidating that a giant "create a group" button yet offers the same functionality. Facebook automatically creates new groups as the student answers three random questions that range from the simple ("What dorm do you live in?") to the complex ("What clubs or organizations are you in?").

The Groups for Schools team (of only four people) has also found that it was able to radically increase participation by including a "facepile" of user avatars in several places during the sign-up process — which helps members see that their friends are already participating in the groups. Facebook thinks of this as the "Social Proof," a way to help users feel more comfortable (and perhaps more compelled) when they join. Users are given the opportunity to invite other students into newly created groups — an opportunity that, on average, results in five invites per group.

Facebook tells us that it's not currently planning on rolling out these types of features to its more general group. We asked specifically if it felt it needed to compete with Google+ directly on this front, as Google has been pushing its Hangouts features as a business solution for some time. Facebook itself uses Groups extensively for its own internal organizations, as Jackson put it, "Facebook runs on these groups." Despite that,, for the time being the company is focusing on offering these new features in a college settings where they can be quickly intreated and refined. A future solution for businesses is definitely not off the table, but don't expect it in the immediate future.

"We plan to roll out new schools every single week, with new improvements in between."

Facebook also isn't attempting to break into the education-software space, instead focusing on more general collaboration tools that can be applied to multiple functions. There are groups for dorms, specific classes, extracurricular groups, housing, and more. Any type of group can be created, but by default Facebook seeds each university with six groups to get things started: Housing, Free & For Sale, Events & Parties, Jobs & Internships, Textbook Exchange, and Campus Tips.

At the schools where Facebook has already piloted the features, the "majority" of students participate, on average joining two to three university-specific groups on top of the other groups they already use. Facebook fully expects that trend to continue as it adds new schools to the program.

Facebook Groups for Schools will begin expanding in the US "pretty quickly," with international schools in the pipeline afterwards.