Many of my Facebook friends, I know simply for the fact that we share an interest in quiz and one of most of my time spent on Facebook is in the any dedicated Facebook Groups to quizzing. I am not sure how to link on here but if I give you the titles of some of the most useful and interesting groups I am currently a member of, they are easily located on the site. If you yourself have any good suggestions let me know in the comments...
Quiz Discussion Group - As the name suggestions this has well over 10k members, is well administrated and proves a good ground for discussion about the world of quizzing
Quiz Questions Group - Some top quizzers and setters present daily questions for you to tackle.
The Contestants - A good group if you are looking for contestant calls or have questions about appearing on TV Shows
Only Connect Questions Group - Again, some of the finest quizzing minds post self-made questions in Only Connect Style. Well worth a look if you are a fan of the show.
Quizmasters - If you host quizzes, a good resource with thousands of files, questions and experience quizmasters always on hand to dish out advice and offer last minute help!