I hope he keeps it up as there is more to it than directly referred hits. Many people will download the font and visit later through the documentation links, or simply remember designer's name after seeing it attached to some fonts and pay a visit in the future. Getting your name out there is always good and I hope he will continue dealing not only with the biggest but also with the smaller but as enthusiastic font sites.
my thoughts are the same, advertising is advertising, no matter how big the scale is. I will try to talk him not to do this...
Dafont is the only site he will get traffic like that from as far as from font sites regarding fonts! Traffic to my site is like 80% from dafont alone. My site sucks but that's besides the point. My fonts dont so people go to my site. When a font of mine drops from the top ten on dafont which they have, I think champagne & limousines is now somewhere between 16-20 on the list, that traffic is cut in half. I do know that abstract is also a top referrer of mine, and I do not place so highly in your top downloads.
furthermore, traffic from dafont far exceeds that of traffic I receive from any other font site.
To be completely accurate I just checked my analytics', and regarding font sites, abstract fonts is my second most referrer, though it refers about 10x less visitors than dafont.
Still, abstract is second. Other font sites follow abstractfonts with equivalently 10x less refers.
Out of the font sites that I have my fonts listed on, no one comes closer to sending traffic like dafont does to my site than this site.
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Unfortunately, the owner of FontFabric don't get more than one hit per day from our site (as opposed to dafont.com with more than 20 hits per day), so he is thinking of removing all his fonts from our site....or at least I'm not allowed to post any of the new ones here.