The Exchange

The Exchange is the official place where creators can share their custom content for The Sims 1, 2 and 3. It is a community feature made available by Electronic Arts. It is free to up- and download from The Exhange once you have registered as a user.

Some creators do not appreciate their work being uploaded to The Exchange. They'd rather upload their work to communities such as ModTheSims. Pay sites in particular are imploring people not to redistribute their content on The Exchange as it is free to use, though there are no legal ramafications for doing so.

Patch
There is a known 'Error code 5' bug with the Sims 2 Exchange. A patch can be downloaded to fix the issue here: http://thesims2.ea.com/community/Sims2SSLPatcher.exe (0.2 Mb)