Mod The Sims
ModTheSims2 (MTS2) was founded by Delphy in May 2004. MTS2 focuses on custom content, most notably Game Modifications. It also has tutorials to make said modifications.
It's sister site, Sims 2 Community appeared around July 2005. The purpose of this was to alleviate the social threads on MTS2, so MTS2 could focus on modifying the game.
Other Sites Hosted by MTS2
MTS2 also hosts other sites on its server, such as MikeInside, TS2 InSIMenator, Simsistic Downloads!, Sims2Pack Clean Installer, Helaene, and Sapphire Sims 2. Even though it's not listed, MTS2 also hosts More Awesome Than You.
Content
Modthesims 2 boasts content for mods, pets, sims, furniture and build mode.
Adult Content
While adult content and less risque content used to be in the same place, adult content was firstly moved to a different section of the site and then given it's own site, SexySims2, for the benefit users of the site who want to spice up their game in a different way.
Not a pay site
Modthesims 2 promises never to be a pay site. With its reputation as such, its huge community and its vast number of downloads, it's one of the most popular sites on the net.