Some quotes from Steve Smith in his column Follow the money in Econtent March 2007 Vol. 30 Iss. 2:
“Buying traffic is the easy part. Keeping those eyeballs is where things get dicey… The problem with buying traffic from search is that unless you have a strategy for converting those new users into brand loyalists, you will find yourself repurchasing that eyeball again and again. Maybe that is good for ecommerce, but it seems to me a disastrous strategy for content…”
“…the smart SEM strategy always combines with good SEO. You learn from the successful keywords you buy in order to optimize the page and get those same results free from organic search the next time. But that stratgey, while less costly, still keeps a site addicted to the new opiate of content, search”.