We never got involved in a cell group- some church's call them home groups I believe- unless this is refering to something different. Basically it is a way of getting people into smaller fellowship groups that meet at various times durign the week so they can be more plugged into the church. So they will have a closer network of support and a way to make friends and fellowship more easily.

Edited to add: I don't think it is a bad idea, as long as the groups are not used as a means of control or tracking members for the higher leadership or a means of developing a shepherding pyramid type scheme in the church.
I'm mortified... petrified... stupefied... by you.
John Nash, A Beautiful Mind