InformationWeek has an article about the rising tide of splogs out there. Splogs are spam blogs - and with so many free services (MS Spaces, BlogSpot, etc) out there, they are easy to put up. Heck, you can buy tools for it now. It's all pretty simple: you get one of the tools (or script one; automating the creation of blogs is not particularly hard), and then send your bot off to scrape content. Presto: Instant Splog. The purpose?
The people who create splogs--or, more accurately, the people who write the programs that create splogs--rarely intend for anyone to actually read their posts, which are often poorly written or even strings of nonsensical words. They're just building a giant clump of links that refer back to other sites, perhaps those that promote gambling or sell Viagra. When people click on those links, they increase the page rank of those sites on various search engines. Splog creators also sometimes include on their splogs ads that generate a small commission, usually a fraction of a dollar, for every click.
Here's one scenario: You want to test out a new programming language, so you run a blog search on it, hoping to find out about others' experiences with it. You end up at a site that looks like a blog--including a supposed blogger's name, photo, and archive of postings--but click on a posting, and you end up at a site advertising hard drive repair.
The search providers - from Google on down to blog specific sites like Technorati - are fighting this. The fact that I still get plenty of spam in my email inbox doesn't fill me with confidence about the end results though. Some of my search feeds are getting to be as useless as email because of this.