One reason I avoid using pure black or pure white these days is I blend text towards whatever is behind it. Text tends to look a lot heavier on the screen than it does in Photoshop (especially if the designer likes to use lighter font weights which generally don't work for the web), and you can really mitigate how heavy the text feels, and reduce the contrast (which mimicks the superior rasterisation going on in Photoshop) by moving the color of the text towards the colour of its background. If you have black text on brown, make the black text slightly brown, for example.