tedster - 7:11 am on Feb 12, 2008 (gmt 0)

If a url depends significantly on on-page factors for its ranking on a given search, then changing that content can even undermine those rankings. It also can make backlinks irrelevant to the current content. Why give Google a moving target to try to scorre?

However, many pages rank predominantly because of backlinks and anchor text, and they can certainly be changed on a frequent basis. A "What's New" segment is important on many types of sites - and what is a news site without fresh news, for example? But then again, how much do sites like CNN care about ranking the Home Page for anything but their domain name?

There's just no one-size-fits-all rule. How much to vary a Home Page is definitely a site-specific decision. Doing it just to be "fresh" is not too wise, in my opinion.

I think there's a lot of mythology around keeping pages "fresh". Adding new content on a new url - that's something else. But I think some people are not very discriminating about the difference between changing content on existing urls and adding new urls.

Part of the concern with changing content comes from earlier days when crawling and indexing was slower. The idea was that if Google saw changed content whenever it spidered, then it would spider more often and somehow that would help rankings. But today, the crawl team has complex algos to determine frequency of spidering -- changing up a bit of text on the page, or intentionally setting the server to never show a 304 response won't change crawl frequency nearly as much as getting lots of backlinks does.

Summing up - change content on an existing url when it makes sense for your site, and don't think of it as a trick of some kind to improve rankings.