http://www.pcmag.com/article2/0,2817,2397158,00.asp is a year old, but its message is still true: "Sure, anyone can make a site that works in Chrome, so it is open in that sense. But if that site only works in Chrome and not in other major browsers, we have a lack of openness in the Web ecosystem."
I wrote a library to abstract the code needed to access the user's webcam through the browser. I had to hold off an experimental launch for around 3 months before I could say it was widely supported, and not just by Chrome.
For experimental stuff, I don't think it's reasonable to hold back like that. It's a great way to check the robustness of an implementation, or the viability of an idea, before it becomes mainstream.