How facebook group Posting can be effective-
This is Just an estimate
If you post On 30 groups daily and if on average 5000members are there in the group .
Total Number of members - 30*5000=150000 Members
If 1% group Members Only see Ads = 150000*1%=1500 Members Viewing ads.
If out Of these Views Only 3% clicks Then You are getting =1500*3%=45 targeted clicks
45 targeted clicks *30 days = 1350 Targeted clicks
Now Only 3% signups for the site out of these clicks you get = 1350*3%= 40 signups a Months .
It can be Increased To Great extent .