Facebook selling groups...why do the admins bother

Hi, can anybody enlighten me on this....Ive bought and sold a few items on a local facebook group. The one Ive recenty used has got loads and loads of members and the admins are seemingly quite busy with ensuring people keep to their terms and conditions,

 

My question is - why do the admins set up these groups? They dont make any commision on sales. And as far as I can establish, they dont get paid for any of the facebook ads.

 

But there are literally hundreds of these groups - and a lot of them seem to involve a lot of messing about checking posts etc.

 

Surelly they dont do this for no recompense at all.

 

Cheerio

 

Chavvy