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

Futura® Bold

Neue Helvetica® 45 Light

Neue Helvetica® 35 Thin

Neue Helvetica® 55 Roman

Neue Helvetica® 75 Bold

Univers® 57 Condensed

Garamond 3 Regular

Bauer Bodoni® Black Italic

Garamond 3 Italic

Avenir® 85 Heavy

Neue Helvetica® 46 Light Italic

Avenir® 35 Light

Helvetica® Condensed Bold

DIN 1451 Engschrift

Futura® Bold Condensed Oblique

Sackers™ Gothic Heavy

Sackers™ Gothic Medium

Futura® Medium

Neue Helvetica® 25 Ultra Light

Linotype Didot® Bold

Linotype Didot® Italic

Avenir® 65 Medium

Linotype Didot® Roman

Avenir® 95 Black

Trade Gothic® Bold

Trade Gothic® Condensed Bold #20

Avenir® 55 Roman

DIN Next™ Condensed Bold

Neue Helvetica® 77 Condensed Bold

Laurentian™ Semi Bold Italic

Linotype Univers® 620 Condensed Bold

Trade Gothic® Roman

Neue Helvetica® 65 Medium

Futura® Book

Neue Helvetica® 47 Condensed Light

Linotype Univers® 420 Condensed

Futura® Heavy

Avenir® 45 Book

ITC Avant Garde Gothic® Book

DIN Next™ Bold

Trade Gothic® Bold #2

Linotype Univers® 320 Condensed Light, Extended

PMN Caecilia® 75 Bold

Univers® 47 Condensed Light Oblique, Extended

Neue Helvetica® 77 Condensed Bold, Extended

PMN Caecilia® 85 Heavy

PMN Caecilia® 76 Bold Italic

Trade Gothic® Condensed #18

Futura® Bold Condensed

Futura® Medium Condensed

VAG Rounded™ Bold

DIN Next™ Regular

Monotype Grotesque® Condensed

Neue Helvetica® 37 Condensed Thin

Neue Helvetica® 45 Light, Extended

Neuzeit® Office Bold

Neuzeit® Office Regular, Extended

ITC Avant Garde Gothic® Medium

DIN Next™ Condensed Regular, Extended

Neue Helvetica® 63 Extended Medium

Neue Helvetica® 65 Medium, Extended

Neue Frutiger® Light

Neue Frutiger® Book

Helvetica® Bold

ITC Avant Garde Gothic® Bold

Neue Frutiger® Bold

Trade Gothic® Condensed Bold #20, Extended

Soho® Regular

Trade Gothic® Bold, Extended

Neue Helvetica® 55 Roman, Extended

Neue Helvetica® 67 Condensed Medium

Univers® 67 Condensed Bold Oblique

Soho® Bold Italic

VAG Rounded™ Light

Helvetica® Bold, Extended

Gill Sans® Book

Neue Helvetica® 53 Extended, Extended

Neue Helvetica® 57 Condensed

Neue Helvetica® 73 Extended Bold, Extended

Baskerville Italic

Frutiger® 65 Bold

Helvetica® Condensed Light, Extended

Neue Helvetica® 67 Condensed Medium, Extended

Helvetica® Rounded Bold

Trade Gothic® Condensed #18, Extended

Neue Helvetica® 87 Condensed Heavy

Rockwell® Bold

Avenir® 55 Roman, Extended

Nazanin® Bold

ITC Avant Garde Gothic® Demi

Cachet™ Medium

Clearface Gothic™ 55 Roman

Clearface Gothic™ 45 Light

Helvetica® Light, Extended

DIN Next™ Medium

VAG Rounded™ Black

Trade Gothic® Next Regular

Neo® Sans Arabic Regular

Cachet™ Bold

Nazanin® Light