I instruct my students to spend a lot of attention on the legibility of the PowerPoint slides they use in their presentations. One important factor is to optimize contrast.

I recently discovered that many websites use font color (html code) #666, which is a form of gray. It might be looking better than black, but it is certainly much less standing out.

I cannot post html here, so I cannot show the difference. On my blog I wrote a post using both color #666 and plain black to show the difference.

Why is font color #666 with such a poor contrast so popular?

i'd have thought that #333 would have been a more popular choice, or a better one at least
in print black on white is good but on the screen the contrast may be too high, and so #333 or #666 is chosen to reduce eye strain.

#666 may be also seen as classier, though of course if it may also suffer from too little contrast, one of the pitfalls of designing for a medium where there is no control over , nor specific knowledge of the range of monitors of devices that people view the site on.

Yeah, #666 is a lot softer on the eye when reading a page of text on screen. That and its the devils colour

I actually use #666 alot more on dark or black pages, where white would be too much contrast. But I think the soft look of the 666 on a white background does look professional, but I would never use for the most important content.

because it's a websafe colour

[sarcasm]
to play a joke over christians web developers ?
[/sarcasm]
Ok, I'm going out...

@davemies
Indeed #333 is better