Collis Ta’eed used a brown for his phenomenal tutorial blog psdtuts.com. And previously brown was the background colour oft the entire site. Recently he published a redesign and changed the main background to white.

I think he wants to achieve a better readability because light brown font with a dark brown background looks good but your eyes get tired if you read long text that way.

You can find the brown in the header and I still think it makes psdtuts.com something special and stand out from the rest.