It's difficult to determine how to optimize a website for maximum exposure in Google's search results, especially for online retailers. Last week, Google announced a change to its search algorithm that has webmasters everywhere holding their collective breath.

Google calls the change a page layout algorithm improvement. The company wants to make sure that when searchers click on Google search results, they won't be taken to a page where the content is hard to find.

"Rather than scrolling down the page past a slew of ads, users want to see content right away," wrote Google's Matt Cutts in the company's announcement. "So sites that don't have much content "above-the-fold" can be affected by this change."

Cutts said the change noticeably affects less than 1% of searches globally and explained it was okay to place ads above-the-fold. The change would not affect sites who place ads above-the-fold "to a normal degree," he said. But it would affect sites that "go much further to load the top of the page with ads to an excessive degree or that make it hard to find the actual original content on the page."

And while Cutts tried to reassure webmasters by telling them not to focus on specific algorithm tweaks, with his next breath he probably made them nervous indeed: "This change is just one of the over 500 improvements we expect to roll out to search this year," he wrote.

Search Engine Land's Danny Sullivan did a comprehensive piece on the Google Page layout algorithm change, and he points out that ads on Google's own search results pages push the "content" - the unpaid editorial listings - down toward the bottom of the page.