Yes. Downloads from this site are compatible with both the PC and Mac versions of The Sims. Just install them the same way you would install downloads from any other Sims site.
To contact the webmaster of this site, please send email to keepitsimple@confusticate.com
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On rare occasions I do make a request or two. But for the most part, real life keeps me too busy to both fill requests and create my own ideas. I highly recommend posting your request on the forums at The Sims Resource. Many creators will see your request there, including me, so you have a good chance that someone will be able to fill it.