Here's a ranked listing of Fonts.com Web Fonts' top 100 most used Web fonts for September 2012:

Neue Helvetica

Futura

Trade Gothic

Neue Frutiger

Avenir Next

Gill Sans

Avenir

Univers

Frutiger

DIN Next

Helvetica

ITC Avant Garde Gothic

Neo Sans

PMN Caecilia

Linotype Univers

Trade Gothic Next

New Century Schoolbook

Linotype Didot

Arial

Century Gothic

Monotype News Gothic

Frutiger Next

ITC Garamond

Times

Garamond 3

ITC Century

Twentieth Century

VAG Rounded

Neue Helvetica Arabic

ITC Officina Sans

News Gothic No.2

Eurostile LT

Memo

Rockwell

ITC Lubalin Graph

ITC Franklin Gothic

Harmonia Sans

Frutiger Serif

Bauer Bodoni

Soho

DIN 1451

Soho Gothic

ITC Conduit

Yakout

Compacta

Biome

Optima

Sackers Gothic

Slate

Eurostile Next

Glypha

Georgia Pro

ITC American Typewriter

Trade Gothic Next Soft Rounded

Calibri

Laurentian

Clarendon

Cachet

Akko

Heisei Kaku Gothic

Bembo

ITC Officina Serif

Iridium

Amasis

Monotype Grotesque

ITC Legacy Serif

Egyptian Slate

News Gothic

Monotype Garamond

Janson Text

Plantin

Adelle

Neue Helvetica eText

Univers Next

Agilita

Neuzeit Office

Aachen

Klint

Museo Slab

Museo Sans

Plate Gothic MT

Aeris

ITC Fenice

Futura T

Basic Commercial

Bodoni LT

Abadi

Neue Haas Grotesk

Serifa

M Hei Simplified Chinese

M Hei Traditional Chinese

Franklin Gothic

TB Kaku Gothic

FB Cham Blue

Azbuka

Camphor

ITC Franklin

ITC Stone Sans

ITC Bodoni Seventytwo

P22 Underground

Ryan Arruda is the Web Content Strategist at Monotype Imaging. Ryan holds a bachelor's degree in film studies from Clark University, and an MFA in graphic design from RISD.