Many types of genealogical groups exist on Facebook. Some have a general focus, such as "Technology for Genealogy," where you can get advice on which scanner to buy or how to back up your research, or "The Organized Genealogist," where you can discuss how keep on top of things with checklists or what should go into surname binders. Thomas MacEntee's "Genealogy Do-Over" will give you a whole course on getting and keeping everything in order.
Genealogy and Newspapers
Other groups will help you with aspects of your research. "Genealogy and Newspapers" features various newspaper repositories and helps members locate historical publications. It also has links to online newspaper collections. One of my most-used sites is "Genealogical Translations" -- this group's multilingual members give generously of their time to help others with translations, including interpretations of difficult types of handwriting.
Many groups focus on genealogy in particular areas; since all my family roots go back to Germany, I'm a member of "German Genealogy" and groups for specific areas such as "Genealogia Silesiae Superioris" (for the former German state of Silesia), or "Ahnenforschung im Werra-Meissner-Kreis," a group for a small locality in Hessen. A quick look reveals groups focused on Spanish genealogy ("Genealog"), Irish genealogy ("KC Irish Roots," "Irish Genealogy") and others ("Polish Genealogical Society of Connecticut and the Northeast").
New England Historic Genealogical Society
If you are very lucky (as, happily, I am), you will find a group about one of your family surnames. My mother was a Berneburg, and I found a Facebook group created by a family genealogy society in Germany, the "Berneburg-Werneburg" group. This led to many new sprouts on that particular branch of my tree. Explore your surnames -- you might come across a "History of the Sandrock Family" or "Gorbea Family" group.
And given the interests of today, you might find a DNA group to connect with; I belong to the "U4 Haplogroup" and "German Language Area DNA Research Project" groups.
German Language Area DNA Research Project
Beyond answering members' questions and discussing relevant issues, groups often offer many resources in their "Files" section. My "German Genealogy" group maintains a 10-page Word document on German links and resources, and my "Genealogy! Just Ask!" group hosts an ever-growing surnames list to which you can add your family names.
I personally have received a tremendous amount of help from these groups, and I offer what little I can when the opportunity comes up. We all know that as a species, genealogists are among the most generous and helpful people on earth, and with so many of them hanging around on Facebook just waiting to be asked, you can't afford not to make use of this incredible resource. Start searching for genealogical groups today!
Have you joined genealogical groups on Facebook? How have they helped you?
[5/1/16 Update: I have just learned of Katherine R. Willson's list of genealogical Facebook groups. With over 8,000 groups included, it will surely offer something of interest to everyone. Gail Dever has also compiled a list specifically for Canadian groups.]