Google has been providing free webfonts for a few months. I think more and more websites would start to use it since it's free and easy to install. It could be wise to have a copy of fonts on my own computer.

Here is what I did:

mkdir ~/.fonts # I didn't have it, or you can install it system-wide at /usr/share/fonts
cd ~/.fonts
hg clone https://googlefontdirectory.googlecode.com/hg/ googlefontdirectory
fc-list | grep Lobster # Check if it's installed

That's it. Google has a Code project for these files. The amazing thing is you can update those fonts easily (Fonts has versions, too), just enter the font directory (~/.fonts/googlefontdirectory) and run hg pull. (I think fc-cache would be needed to refresh?)

You will need hg (Mercurial).

Before I found this Code project via FAQ, I tried to find out how many fonts are already available in Gentoo Portage tree. Only three.

Font name                  Package name
Cantarell
Cardo                      cardo
Crimson Text
Droid Sans                 droid
Droid Sans Mono            droid
Droid Serif                droid
IM Fell
Inconsolata                inconsolata
Lobster
Molengo
Neuton
Nobile
OFL Sorts Mill Goudy TT
Old Standard TT
Reenie Beanie
Tangerine
Vollkorn
Yannoe Kaffeesatz

So, manually install from repo is the only option and it definitely will be much faster than using emerge.

On Windows? God help me. On Mac? It's Apple, you are not supposed to install stuff like that. (Okay, I don't know how to install a font on Mac)