LOL. It's currently at 750. 500 was too cheap 1000 too expensive (based on sales volume).
Basically you get some traffic from them. It's just is what it is. A listing in a good directory which helps with search engines. That being said I still have same quality guidelines just lot's of them in entrecard are great blogs so it's really win win. All of the listings old through entrecard are to blogs that meet my requirements. I can never have too many good quality; regularly updated blogs in the directory... Never!
