My OS is Ubuntu and the browser of my choice is Firefox. Some WWW developers seem to be unaware of the fact that not everyone in the world runs Windows and specify only fonts like Verdana, Tahoma, Helvetica or Arial in the CSS files. On my machine such webpages (example) were rendered with a font that looks like Times New Roman and looked really awful.
To solve this problem I installed msttcorefonts package. This solved one problem... And created another one. Google and Gmail started to look worse than they did before.
After some searching I found this thread and enabled autohinting in /etc/fonts/local.conf file. Both Google and Gmail started to look good again. And what's more all fonts on the system seem smoother and clearer.