The LibraryThing Logo
 The FontThomas Paine (see the second font in the image). This appears to be a copy of LTC Pabst Old Style (see the first font in the image), a font designed by Frederic Goudy for the Pabst Brewing Company to use in promotional materials. It's now owned by the Lanston Type Company.
The font in the logo is also compressed horizontally to 75% of the original size (see the last line of the image).