Looks like the Arduino SRL folks finally created a forum.
http://labs.arduino.org/tiki-forums.php
This will really be the indication whether they're able to build any community. The real Arduino guys aren't known for monitoring and responding much on their own forum, so the bar isn't raised very high. Still, I'd guess the odds are very long they'll gain much real community.
I looked at their booth at Maker Faire and chatted with a few of them for a while. They're working on a LOT of boards, mostly different flavors of Yun. One appears to be meant to compete with Tre, using a 560 MHz chip with more memory connected, with info about javascript-based IDE which reads exactly like the stuff Ardiuno.cc announced a year ago for Tre. SRL (aka Linino & cc logistics) seemed to be all about releasing more hardware. I got the feeling they're under the impression the community will magically create code for whatever hardware they make... which works if they copy from the real Arduino, but I believe they're going to be in for a rude awakening as they try to do anything that isn't following closely in Arduino LLC's footsteps.
They're also releasing a board called "M0", which is Zero without the debug chip.
One of their boards was "free dog" based on a Freescale chip and what looked like Yun, and "dog leash" as a jtag/swd debug cable. I'd seen these on the Linino website before, but this is the first time I'd actually seen the real boards. None of them seemed to know much about it. It looked like a they copied one of Freescale's Freedom boards, not Teensy. Musto stepped in briefly and said the project was dead because Freescale stopped communicating with them suddenly and wouldn't even return his phone calls (gee, wonder why!)
The real Arduino booth was mostly about interacting with people one-on-one, showing them how to use the IDE and some boards. It wasn't about selling or promoting projects, and it was 50-50 with Atmel, just like last year.
I didn't see Massimo's speech live, but we did talk in person Friday evening briefly... though people kept coming up and interrupting with whatever thing they *really* wanted to talk about. Most of what we talked about was stuff he mentioned in the speech. Our paths didn't cross again until the final hour after closing Sunday, when we chatted for just a few minutes. PJRC and Arduino will be working more closely, though the only thing that's really planned at this time is we're going to work to the merge changes, rather than letting them go unused.