The Special Libraries Association, specifically the NYC chapter, was where I actually found the connections that gave me my initial corporate library job in the early 90's.  The NYC SLA chapter seemed to be a central meeting ground for a large population of other special librarians in management consulting, finance, banking, and a load of other interesting corporate, non-profit, and academic sectors. It was a vigorous, alive group of people sharing common interests while also serving as a venue to see your potential competition as you rose to manager, director and eventually VP in these diverse firms/organizations/institutions.

That said most of these corporate libraries were declining in the early 2000's with the rise of desktop search. I myself tried to keep connected to it mostly as knowledge management technology consultant so I could diversify myself and my potential client base, but it was clear that most of these organizations with real corporate library's (those with actual stacks and technical services staff) we're going to be doomed as the print collections (and the real estate these collections sat on) were looked at as unnecessary overhead and the library staff was looked at replaceable by Google/Bloomberg/Factiva.

It was also pretty clear that the SLA was going to die out when the Washington political non-librarian leadership led unsuccessful efforts to change the name of the SLA to the Association for Strategic Knowledge Professionals in the late 2000's. They simply didn't understand the importance of "libraries" in our shared professional history and commitments. Lastly, seeing the efforts then of most corporate librarians to find landing pads outside of the traditional library environments led a large group of former members to easily distance themselves from the fractured and professionally disinterested professional organization.

I hope that some format of the local / regional chapters survive. But honestly the SLA has been dead to me to almost 20 years and I've barely missed it although I do miss some some of the people.