It should be alternating lines with red, black and blue not greys, it's to increase reading speed: http://www.beelinereader.com/
Thing is, line-height helps with the same issue (but without the weird colors), so if they'd fix that, the funky colors aren't as useful anymore.
But I guess we gotta save the trees from those printing their web pages or something.
Whatever one may prefer, I see they offer a plugin, which is a better way to use this tech, not by random sites forcing it on us.
If it's super-tight, why did loosening it not seem to help? http://www.gwern.net/AB%20testing#line-height
> Whatever one may prefer, I see they offer a plugin, which is a better way to use this tech, not by random sites forcing it on us.
Is it better? That seems like the sort of claim that should be tested...