Recent survey indicates that developers are choosing MacOS and Linux over Vista. An interesting post in Fortune confirms the feeling that Vista is not very popular among developers and they increasingly choose to work in Linux or Mac environments.
The part of Linux in the market is still less than 1% but the growth is encouraging and as for the question that the article raises:
Could programmers be developing an interest in something beyond the size of the installed base?
I think that we have to remember that the developers might work with a certain OS for several reasons among them are the needs of the companies and applications so if they work with a Linux environment it is not always their choice but rather the choice of the company.
The fact that it usually the firm and not just the individual developer that chooses the OS can be easily seen in firm reports.
SourceForge released the quarterly earnings and the firm analyst says that the Linux server growth is strong.