The apparent going premium of 50 percent for a targeted ad on the Internet suggests that Internet advertising may be as likely to reduce total ad spending as to increase it. The Internet ad market is growing at two or three times the rate of any other medium. So suppose advertisers direct one-fifth of their resources onto the Internet. That would be a tenfold increase in the Internet's share. And suppose the total market for advertising doubled .
Eyeballs are worth money only because they are attached to wallets.
And the size of the wallets is a strict limit on the value of the eyeballs. Free magazine articles are one thing, free computers are another. Exchanging stuff for eyeballs makes sense as long as the cost of providing the stuff is less than the value of the eyeballs to advertisers. What it has cost Slate to provide this article by me can be the basis for a very profitable ad-based business. Take my word for it.