I guest that all of you have added Facebook friends to your profile and have been blocked for adding new friends for some time, am i right Here i will tell you how to avoid this. I am using "Unfriend Finder" addon, with this addon you will have new button in the right corner of your Facebook profile where you can monitor how many friends requests you have send and to mass delete unresponsive friend request. I suggest you to add no more then 30 peoples per day and no more than 3o-50 pending request at any time. You can download the addon here, it is free unfriendfinder.com
I wouldn't use something like this, 30 people per day is too many and will send up a red flag on your account.