Here's a ranked listing of Fonts.com Web Fonts' top 100 most used Web fonts for October 2011

Futura® Bold

Neue Helvetica® 35 Thin

Neue Helvetica® 55 Roman

Avenir® 55 Roman

Avenir® 85 Heavy

Univers® 57 Condensed

Neue Helvetica® 75 Bold

Garamond 3 Regular

Garamond 3 Italic

Avenir® 35 Light

Neue Helvetica® 45 Light

Bauer Bodoni® Black Italic

Helvetica® Condensed Bold

Sackers™ Gothic Heavy

Avenir® 65 Medium

Sackers™ Gothic Medium

Avenir® 95 Black, Extended

DIN 1451 Engschrift

Neue Helvetica® 25 Ultra Light

Futura® Medium

Trade Gothic® Condensed Bold 20

Avenir® 95 Black

Linotype Univers® 620 Condensed Bold

Trade Gothic® Bold

Neue Helvetica® 77 Condensed Bold

Linotype Univers® 420 Condensed

Futura® Book

Linotype Didot® Bold

Linotype Didot® Roman

Linotype Didot® Italic

Linotype Univers® 320 Condensed Light, Extended

DIN Next™ Condensed Bold

Univers® 47 Condensed Light Oblique, Extended

Neue Helvetica® 67 Condensed Medium

Trade Gothic® Roman

Futura® Bold Condensed Oblique

Neue Helvetica® 65 Medium

Avenir® 45 Book

Futura® Bold Condensed

Trade Gothic® Condensed 18

Futura® Medium Condensed

DIN Next™ Bold

Futura® Heavy

Trade Gothic® Bold 2

PMN Caecilia® 75 Bold

PMN Caecilia® 85 Heavy

Laurentian™ Semi Bold Italic

Neue Helvetica® 45 Light, Extended

Monotype Grotesque® Condensed

ITC Avant Garde Gothic® Book

PMN Caecilia® 76 Bold Italic

Trade Gothic® Bold, Extended

Neue Helvetica® 47 Condensed Light

Trade Gothic® Condensed Bold #20, Extended

Trade Gothic® Extended Bold

Neue Frutiger® Book

VAG Rounded™ Bold

Neue Frutiger® Bold

Neue Frutiger® Light

Neue Helvetica® 55 Roman, Extended

Neue Helvetica® 57 Condensed

Helvetica® Bold

DIN Next™ Regular

Administer BookItalic

Neue Helvetica® 87 Condensed Heavy

Neue Helvetica® 37 Condensed Thin

Helvetica® Bold, Extended

Rockwell® Bold

Avenir® 55 Roman

Univers® 67 Condensed Bold Oblique

DIN Next™ Condensed, Extended

Trade Gothic® Next Regular

ITC Avant Garde Gothic® Medium

Neue Helvetica® 63 Extended Medium

Neue Helvetica® 53 Extended, Extended

Felbridge™ Regular

Neue Helvetica® 73 Extended Bold, Extended

VAG Rounded™ Light

Gill Sans® Book

Trade Gothic® Next Condensed Bold

Trade Gothic® Bold #2, Extended

Neuzeit® Office Bold

Neuzeit® Office Regular, Extended

Frutiger® 65 Bold

ITC Avant Garde Gothic® Bold

Futura® Book, Extended

VAG Rounded™ Black

Helvetica® Bold Italic

Frutiger® 55 Roman

Rockwell® Regular

Neue Frutiger® Regular

ITC Lubalin Graph® Book

Avenir® Next Demi

Trade Gothic® Condensed #18, Extended

Neue Helvetica® 65 Medium, Extended

Cochin® Roman

Neo® Sans Regular, Extended

Eurostile® Next Regular

Linotype Univers® 520 Condensed Medium

Frutiger® 45 Light, Extended