I'm a solo practitioner (for the most part) and quite frankly found that answers on this site bootstrapped me over the years into a better SFDC admin/developer (others on the site could argue whether I'm sufficiently "better") but I know that I've improved a lot.
SFDC is an interesting system in that it is reasonably accessible to casual developers (point and click configuration, simple triggers, simple VF pages) and as such the community needs the help from folks who have been there and can assist quickly.
As such, and perhaps lacking other outlets to contribute to a community, I find this to be a site where I continually learn from others (I mean you Keith C and sfdcfox, among others), have a chance to revisit and cement my knowledge by working on other's issues and hence save them time, and enjoy the recognition that is generously proferred.
The user interface is clean and far superior to the the SFDC Developer Forum where I have ceased to visit except when directed via a Google search.
The system also is well-moderated and avoids the self-promotion or religious wars found in other forums (which turn me off) - as such, the weltanschauung of SFSE matches my own outlook.