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

Trade Gothic

Neue Helvetica

Avenir Next

Univers

Avenir

Proxima Nova

Helvetica

Frutiger

Gill Sans

Futura

Linotype Univers

Klint

DIN Next

Museo Sans

Museo Slab

Century Gothic

ITC Avant Garde Gothic

Neo Sans

Chaparral

Arial

Rockwell

Myriad

Motoya Birch

Eurostile LT

Univers Next

ITC Legacy Serif

ITC Lubalin Graph

ITC Caslon No. 224

ITC Century

VAG Rounded

Soho Gothic

ITC Franklin Gothic

Optima

ITC Legacy Square Serif

Trade Gothic Next

Neue Frutiger

Swiss 721

Soho

Swift

Neue Helvetica eText

Helvetica World

Minion

ITC Officina Serif

Frutiger Next

Linotype Sketch

ITC Charter

Gill Sans Infant

Francker

Adobe Garamond

Bookman Old Style

Linotype Didot

PMN Caecilia

Auriol

Humanist 777

Slate

ITC Officina Sans

ITC American Typewriter

ITC Conduit

Bodoni LT

Rotis Sans Serif

Lexia

Copperplate Gothic

ITC Stone Informal

ITC American Typewriter Hellenic

Trade Gothic Next Soft Rounded

Egyptienne F

ITC Fenice

Calibri

Rotis II Sans

Delima

Monotype Goudy

Bembo

Droid Sans Mono

Adobe Caslon

Novecento

Droid Serif

Effra

Monotype News Gothic

C Hei 2 PRC

Copperplate

Baskerville Classico

Orator

Caslon Classico

M Elle PRC

C Hei PRC

M Lady PRC

M Stiff Hei PRC

ITC Stone Sans

ITC Stone Serif

Sackers Gothic

Twentieth Century

Amasis

Plantin

Monotype Garamond

Lucida Sans

Droid Sans

Azbuka

Museo

Comic Strip

Grocers