Well, I doubt that it is monitor itself: I capture screen, and I see it on captured picture, so it's exist. 
But resolution definitely could be the reason: I have 1280x1024 in fullscreen and 1280x960 in window. Effect exist in both settings.
Font smoothing work, but not in needed direction. Look:
This was image with font smoothing on, exactly as previous shot. But if I'll try to disable it, picture definitely degrades:
Here even clear fonts gain blurness! And flavor remains same blurry as before... Hmm, it gave me idea: both fonts looks identical for now. So maybe flavor text simply don't processed by smoothness algorithms somehow?
