Here's a listing of the top 100 most used fonts from the Fonts.com Web Fonts service for February 2014:

Trade Gothic

Avenir Next

Neue Helvetica

Univers

Proxima Nova

Avenir

Gill Sans

Frutiger

Futura

Helvetica

Museo Sans

Linotype Univers

Museo Slab

DIN Next

Century Gothic

Klint

Chaparral

ITC Avant Garde Gothic

Myriad

Rockwell

Arial

ITC Legacy Serif

Univers Next

ITC Century

Eurostile LT

Brandon Grotesque

Neo Sans

VAG Rounded

ITC Caslon No. 224

Motoya Birch

Optima

ITC Lubalin Graph

Gill Sans Infant

Amasis

ITC Franklin Gothic

Soho Gothic

ITC Legacy Square Serif

Neue Frutiger

Trade Gothic Next

Swiss 721

Neue Helvetica eText

Linotype Sketch

Oxygen

ITC Charter

ITC Officina Serif

Bree

Frutiger Next

PMN Caecilia

Swift

ITC Conduit

Lexia

Bodoni LT

Azbuka

ITC Officina Sans

Linotype Didot

Bookman Old Style

Calibri

Soho

Humanist 777

Rotis Sans Serif

Delima

Trade Gothic Next Soft Rounded

ITC American Typewriter

ITC American Typewriter Hellenic

Adobe Garamond

Auriol

Helvetica World

Caslon Classico

Bembo

Glypha

Neue Helvetica Arabic

ITC Fenice

Monotype News Gothic

ITC Stone Informal

Egyptienne F

Copperplate Gothic

Novecento

C Hei 2 PRC

M Elle PRC

C Hei PRC

M Lady PRC

M Stiff Hei PRC

Adobe Caslon

Perpetua

Monotype Goudy

Francker

Baskerville Classico

ITC Eras

Droid Serif

Bodoni

Orator

Droid Sans Mono

Twentieth Century

Rotis II Sans

Sackers Gothic

Comic Strip

Monotype Garamond

Inform

Museo

Akko