Retaining the members

Trying to get people to register is one thing but retaining or getting them to come back to the site is another. What are some of the things you guys do out there so your members stay and come back to the site. Are there any game mods like Facebook that you use or any activities that you do?

The best way is to try to cater to a specific niche, and provide the features that they especially want. Do that, and they will surely keep coming back, as I have found out. Also, try laying out mouse traps around the web site and see if anyone gets stuck. With a broken leg, they ain't goin' nowhere.

Simple!  Make a one-way door, they enter but take the handle off to leave and you'll get a huge collection of members

But follow what Magnussoft said, you need to have a place in the market.  You cannot take the jack of all-master of none approach.  You need to think to yourself, why would I want to join (besides it being your site) and what benefit does it give me.  What entertainment value can you offer, music, picture trading, hooking up, virtual gallery, the options are endless and you need to chose one and become a master.