I would have to place the blame mostly on the search engines themselves.
They were the force behind the “SEO”. Why would you show backlinks and other information for a website? I mean, when would a regular Internet user check, even care about, the backlinks of a website? Or how many other pages “contain the term”? Never.
If the SEs would have kept secret to how they rank websites, this would have never happened. Webmasters are human, too, and most of them would do anything to make more money. Sad but true.
If the search engines leave something that could be manipulated, well, it will be manipulated.
And what is the difference between exchanging links with, for example, hotel-related website, and buying a link on hotel-related website? None, except the price. Either way it’s unrelated website…
Then, what is the difference between exchanging links with hotel-related website and posting a message on hotel-related blog? The only difference is that you did not ask for permission, but generally speaking, you have been granted the permission to post anything on a blog, even an URL, every blog gives you the option to post URL, which means you are encouraged to post your URL…
Don’t get me wrong (because I know you will 
), all I’m trying to do is look at things the way they really are.
On another note, 1 of every 4 spam emails are for Viagra. Pfizer, the maker of Viagra is teaming up with Microsoft to reduce the spam…