I have known many homeschoolers over the years that swear by their support group and claim that without it, they would be lost. For those not in the loop, a home school support group is designed to get homeschoolers together to socialize, to help and support new homeschoolers, to organize and plan field trips together (with the added benefit of being able to get a group discount), and to have an outlet that can help out when things get stressful.
People always ask me if I run or belong to one. The simple answer is that I do not because it is not a great fit for my family. Running and organizing a group takes an enormous amount of organization and time that I just do not have and being a productive member demands a fair amount of time in order to benefit from membership.
Even though we opt out of joining (or running) a group, most home school groups are wonderful outlets for new parents to the home school lifestyle. They can help ease the transition from the role of parent to teacher and from the role of child to student. Believe it or not, children and parents DO get confused when their roles are changed within a family setting.
Whether you belong to a group or not, you will need a support system to help cheer you on when you doubt yourself and encourage you when you get overwhelmed. It is very hard to home school without someone else to bounce ideas around with or to just call and vent. Therefore, if you choose to skip the group then make sure you have a solid back up plan that includes plenty of encouraging friends or family members.