SCEA is not planning to implement a internet browser plugin for COLLADA ourselves. If anyone is interested in implementing a browser plugin please send me an email so we can coordinate that effort as well.
That being said, I would expect anyone working in the internet/web domain to consider X3D as their format before COLLADA.
The big disadvantage for X3D is that the browser-plugins are developed by fairly small/unknown third parties; when putting these into practice in the (near) future there will be a rather big amount of user/clients that will see these unknown plugins as a risk to their computer/privacy. (That is if Windows hasn’t blocked the plugin out in advance, such as with Java applets and XP Service Pack 2.)
A good possibility would be to develop a Collada viewer/player with Microsoft.NET; I’ll have our company look into this a.s.a.p. and will keep in touch.
If anyone has a good idea on this subject I’d be happy to hear (so next to Collada being the “No.1” interchange format, we can also finally grow to “1” format for distributing it on the Internet (instead of the 80 or 90 3D webplayers currently existing/being developed!)