Remember the whole kerfuffle on 18 March 2008 when Apple pushed out a Safari "update" to Windows iTunes users? (screenshot below) People had a problem with the fact that Apple also included Safari 3.1 with their Software Update service on Windows and it was labeled as an update with the option to install pre-selected.
According to the latest stats from Net Applications, Apple's gamble may have worked. Witness the end of the graphic below:
Safari 3.0 on Windows never gained much market share, peaking at .07%. However, Safari 3.1 on Windows is rapidly gaining market share, already tripling Safari 3.0's peak.
On 18 April 2008 Apple changed the behavior of Software Update on Windows and now lists Safari as "new" software if it's not already installed.