A good friend of mine is an ID, so i posed the question, and got all this in response:
The biggest Industrial Design community is the IDSA | Industrial Designers Society of America (http://www.idsa.org
.) You do have to pay an annual fee to become a member, but even without being a member their website has job and contest postings that are neat to check out. If you're a member you get newsletters and shit, but membership isn't cheap. I believe for a professional level membership it's around $500 a year. They also host regional and national conferences which can be great for networking (last year they hosted 7 conferences in total; Western, Central, Southern, Midwest, Northeast, International, and Medical design.) The conferences are usually a multi-day event and include lots of speakers, presentations, local design studio tours, and networking drinking get togethers. You do not have to be a member to attend, but the conferences are paid events.
There are several "groups" on LinkedIn you can become a part of such as Industrial Design (members only, but they just have to approve you), IDSA (you do not have to be a paid member of IDSA to join the Linkedin group) and it sounds like he's already familiar with Core77, but they also have a LinkedIn group.
It's also pretty cool to follow some of the larger ID companies on LinkedIn ( I might suggest Ammunition, Teague, Porsche Design Studio, IDEO, fuseproject, Astro Studios, frog, Continuum, LUANR Design, and Phillips Design if he's unfamiliar with the big dogs.) They'll usually post links to articles they find interesting and recent work they've done/awards they've received...and sometimes the comments section on the things they've posted get pretty active.
As far as posting your own work and being able to see the work of other designers Behance (https://www.behance.net
) is, in my opinion, totally the best thing out there right now. You can search by "creative field" to find work that is specifically Industrial Design. If you have a profile (you don't even need to post your own work to have one) you can appreciate others projects, save projects to "collections" to reference later, and follow other creatives. Once you start following others you get an "activity feed" with projects people you've followed have liked....which is cool. There are also galleries and collections of "featured" work, so you can see some of the stand-out projects without poring through a million pages.
) used to be big like 6 years ago, but it's not so popular anymore. On Coroflot you can post your own work, see the work of others, and they also have a job postings section.
) is cool for making your own portfolio site, and you can follow others, but it's not specifically for designers...more all-inclusive-artsy...but very pretty and cool to checkout.