Search Engines Try To Block Blog 'Comment Spam'

Key search engine companies Google (Nasdaq: GOOG), MSN and Yahoo (Nasdaq: YHOO) as well as Weblog tool provider Six Apart have united to stop "comment spam," but one search engine expert does not think the effort will slow the practice.

Most bloggers allow reader responses to entries. This also opens the door to spammers, who use automated programs to post links to their own Web sites in the comments sections of blogs. The links, and the words within them, have some effect on the spammers' site ranking within search engines.

Adding a Tag

The measure announced late yesterday supports an HTML tag called "nofollow." When attached to the end of the spammed hyperlink, it signals search engine crawlers to ignore that link. The goal is to take away the incentive for posting such links.

The tags would be added automatically to posts through updated blogging software. If you don't want the tag there, you would have to remove it manually.

"It may help," Danny Sullivan, editor of SearchEngineWatch.com, told TechNewsWorld. "It isn't going to stop comment spam. What it may do is make it a little less attractive. It's not a magic bullet."

There are many holes in the solution, he said.

Bloggers must each set up their sites to accommodate the nofollow tags, for one, he said. Sullivan has written an article describing how to do that.

"People want the links even if they don't affect their Web rankings," he said. "And they may think, 'I'm running automatic tools, so why not keep placing the links?'"

In other words, generators of comment spam are unlikely to change their habits because automatic tools make mass postings effortless. Even if the percentage of untagged links is low, the spammers would still get benefit from them. And even the tagged links still work, so they could still get click-throughs from their placement.

Implementation Coming

The rel="nofollow" tag is already a part of HTML, and Google's crawlers already recognize the code. Yahoo said it will begin support within a few weeks, and MSN will follow later this year with the switch to its own search engine.

Six Apart will release a plug-in for its software, Movable Type.

Many factors play into search engine rankings, so while one extra link won't change a ranking, a 1,000 is likely to, Sullivan said.

Individual bloggers can do a lot to limit the amount of comment spam, he said, first by adding the nofollow tag, but also by taking such steps as requiring registration in order to post, creating a black list of those banned from posting and adding a graphical code that must be viewed and retyped as confirmation that a real person is attempting to contribute.