For whatever reason, the E language's actor model was the most influential on IMVU's concurrent programming model (in Python). I highly recommend taking a glance through the language description.
Hmmm.... when did the "p2p scripting language" tag get added to the general description? Ever chasing salvos when it comes to fads it seems. While E is/was pretty cool, the mental overhead required to jump to it from Java (given the general pool of java coders) seems to have been too high of a hurdle for any sort of critical mass to develop. I have higher hopes for Caja (the capability-security enhanced javascript that markm and a couple of others in this area are working on at Google.)
"p2p scripting language" has been around for as long as I've been involved in the project. According to the Internet Archive, http://web.archive.org/web/*/http://www.erights.org/ , it was added in November 2000.
The web site's approach hasn't really been redesigned in a long time. We're chronically short on people-with-spare-time-to-think-about-this-stuff, especially now that MarkM is working at Google (and previously doing a PhD). I myself don't have much spare time either.
I think Caja definitely has the greatest potential for mainstream adoption of object-capability+event-loop systems right now, but E is still the “designed for capabilities” language for me, and so I use it for most of my personal programming (data munging, generating my packing list, interactive this-and-that, etc) when I can, so that I can feed the experience back into the design/implementation work for E.
[Just registered on HN; this was the first thing I had to say important enough to bother for.]
If you're in to capability security check out the Cap-Talk mailing list: http://www.eros-os.org/mailman/listinfo/cap-talk