> In the past, the advertiser would likely to tell that to the people selling ad space.
Prior to ad networks that automatically match advertisers to display space, yes.
The thing is, though, prior to ad networks, there were a lot fewer advertisers who were interested in spending time and money on doing this song and dance with a slew of tiny web properties. Most of them wouldn't even bother.
You can have no ad networks, or you can have a long tail of low-prominence websites earn ad revenue. Pick one.
1. Low prominence newspapers made most of their money from classifieds. Craigslist ate that business.
2. A low prominence local newspaper has local businesses advertising in it. Your local auto mechanic on Walker Street will buy an ad in a local paper, but they aren't going to spend a penny to advertise directly on your website, even if it has the same readership #s as the paper. Because 99.9% of your website's visitors aren't within driving distance of their location.
The ad network [1] solves problem #2, by making it possible for geographically-constrained businesses to buy ad inventory on websites that only get a handful of clicks from their geographical area.
Yes, ad networks introduce plenty of problems, as people in this thread point out. [2]
No, nobody will advertise on your 1,000-50,000 reader/day website without going through an ad network. Small advertisers aren't going to pay anything for an untargeted impression, and large brand advertisers aren't going to waste their time [3] on so few impressions.
[1] I am speaking about the industry as a whole.
[2] I could mention a few other problems that people in this thread haven't pointed out, too, but that's neither here nor there.
[3] Not to mention that without going through an ad network, and by directly dealing with the website operators, making reports of your ad spend + ROI becomes a colossal pain in the ass. People who work for large advertisers are just trying to do their job, and their job consists of making their boss happy. Something that does not make their boss happy is being unable to quickly say how much money they spent, and what they got for that spend.
Prior to ad networks that automatically match advertisers to display space, yes.
The thing is, though, prior to ad networks, there were a lot fewer advertisers who were interested in spending time and money on doing this song and dance with a slew of tiny web properties. Most of them wouldn't even bother.
You can have no ad networks, or you can have a long tail of low-prominence websites earn ad revenue. Pick one.