First make sure your web design is compatible with IE, Firefox, Opera and Safari, and the rest are too small to really worry about at this stage. SEM Insights Blogs Conferences Tools Feeds About June 6th, 2009 Email Club Sign Up Get the RSS Feed.
My rule is to test anything that has higher than 2% market share, which currently means ( according to Royal Pingdom ): Internet Explorer, Firefox, Chrome, Safari and Opera. See this post for more tips - Choosing the Right Keyphrases - from Sam Crocker. #17