Professional Communities Online
One startup area I’ve been thinking a fair amount about lately is professional communities. Some thoughts follow:
The web has long existed as a place where people with particular interests congregate. While I don’t have particular examples of *professional* communities that have been in existence for awhile readily available, I’m certain they’ve existed historically (though perhaps more as utilities / shareware and forums, and less as for-profit entities).
Post-Facebook, one might think of professional communities as specialized instances of the social networking model — not merely interest-based, but profession-based social networks, based on the concept of someone having a ”profile” (or perhaps “portfolio” in the professional context). Professional communities also often simultaneously serve a marketplace function, bringing buyers and sellers together, but I think of professional communities as something more than just serving a marketplace function.

There are a few recent prominent examples of interesting professional community startups that come to mind. GrabCAD is a mechanical engineering community, and Academia.edu is a community for academic researchers. The market for academics is certainly large, and as has been well-chronicled elsewhere, academic publishing is ripe to be “disintermediated.” And while presumably smaller, a community for mechanical engineers to meet, get technical feedback, and share 3D CAD models (and find manufacturers/customers) also makes sense, to the extent that these are professionals with a specific area of technical expertise that can benefit when their peers comment, critique, advise, etc. [This is distinct from building actual CAD modeling software, which itself is ripe for innovation too, as was reported recently.]

I think I’d also add something like Visual.ly to this list, at least the side that focuses on allowing “data visualizers” to share their portfolio of work (as opposed to their new feature that enables users to generate quick customized infographics — in itself a very cool and interesting idea). Skillshare might also fit into this category, though they’re less focused on a particular profession, and more on the marketplace concept of bringing together “buyers” and “sellers” of non-academic knowledge (though there certainly is a strong community feel among Skillshare users).
These are surely just a few examples of the many out there — I’m sure professional communities like this exist, or should exist, in the medical arena, for example. There are also surely more examples where vertical/profession-specific community sites have failed than have succeeded. I think at least part of this is because community-focused sites (and social-networking style sites broadly) suffer from the problem of trying to create something that requires network effects to succeed at scale.
Why are startups such as these burgeoning now (putting aside for the moment the very real possibility that this isn’t a new phenomenon but that I’m just now becoming more aware of them)? I think there are at least a few factors. One is the previously-mentioned social networking model that created the template for profession-specific communities and more broadly enabled and created comfort with sharing online.
Another is simply improving web technologies — I don’t think you saw communities focused on 3D CAD modeling or on infographics/data visualization until now because these are fairly rich mediums and technologies, and perhaps couldn’t flourish in an environment in which the subject matter couldn’t be fully appreciated online (though this argument is less applicable to something like Academia.edu which doesn’t necessarily involve rich technology-driven products).
I think other important characteristics required for such professional communities to flourish online are (i) the profession or industry in question probably needs to be one in which sharing and soliciting feedback is valued and important, as would seem to be the case in the examples mentioned above, and (ii) it should also ideally be an industry that conducts some meaningful portion of its business online.
UPDATE: Behance is another awesome startup in this category. It enables showcasing and discovery of creative professionals’ portfolio work, and also serves a marketplace function, bringing creative professionals and companies seeking talent together.