According to a recent survey by Evans Data, Windows as a platform is facing developers losing interest in creating programs for it. It seems that there was a significant decline in Windows development, as high as 12% over the past year, from 74% to 64.8%.

Rather, it seems the developers are targeting other platforms more, particularly Linux, which gained developer targeting by as much as 34%. It seems Red Hat and Novell are picking up a lot of talent, at the expense of Windows. As for the impact that the release of Vista had on these figures, one analyst is claiming Vista only helped the situation "from getting worse":

The arrival of Windows Vista likely only kept the numbers from being even worse. "I think Vista probably offset some of the decline," Andrews said.
The decline is expected to continue, with another drop of about 2% over the next year. The survey factored in both client and server application development, and assumes that the decline began about two years ago and is accelerating. But why?

Microsoft did not comment on the data, and no stats were given for other platforms such as Mac OS or Unix.