I’ve just come across riastats.com which has statistics on which RIA (Rich Internet Application) plug-ins are installed on which browser.
The stats are from a relatively small sample: it claims to have analysed 1.5 million browsers across 42 sites at the time of writing.
The headline: Flash is on over 97% of browsers; but only 52% are at version 10. Java is on just under 75%, while Silverlight can only muster 20% penetration.
I also noticed that Firefox (25%) users are more likely to have Silverlight than IE (20%). Maybe all those locked-down corporate desktops.
Another snippet: less than 30% of Linux users have Sun’s Java plug-in installed.
Microsoft can take some comfort from the direction of the graph. In December 2008 only 15% of browsers had Silverlight. That’s pretty fast growth.
Still, the bottom line is that if you want to be fairly sure that your users have nothing to install in order to view your RIA content, use Flash. But stick to version 9.