PSi doesn't do a whole lot for me, and my membership in PSi doesn't do a whole lot for me, either, but PSi does a lot for the art form/ art movement I support, and you all seem like nice people, and $35/yr is a modest donation to the cause of good writing and good fellowship.
I joined in 2007 (2006?) back when I wanted to be a slam poet. Membership gave me a cute card (which I soon lost) and permitted me to enter upper-level slam tournaments at the Cantab. It was a means to a very specific, practical end.
By 2008, I'd realized that I had more to offer as a booster and backstage guy than as a competitor, but I paid the modest renewal fee because I didn't want PSI to delete my account and I did want a discount on a hotel room @ NPS Madison.
In 2009, I renewed at the associate level so I could sell my book in the PSi store. I forget whether it got me a discount admission to IWPS Berkeley.
Now it's 2010, and I'm about to renew my membership because I'm pretty sure i'm overdue for renewal, but I haven't gotten any reminders and, obviously, I can post comments and see "members only" parts of the forum. The book isn't selling (here), and the ways I participate in the slam community don't require my continued membership to PSI, but as I said at the start, it's just $35/year, PSI is Good People, and it's for a good cause.
I suspect the rank-and-file members of a given slam/open mic community have no idea what PSi is. It's like asking college students about the board of trustees, or the you-gotta-be-kidding letters that invite me to annual shareholder meetings of my meager stock portfolio. The work PSI does is always important but rarely visible. The Boston Poetry Slam has a dozen staff members and only three of us (Simone, Dawn, and I) post on these forums with any frequency. Our community is intensely loyal to the Cantab, and has a good spirit about the NorthBEAST slam family, but PSi just isn't on our community radar.
I suspect PSI will be a much bigger part of the Boston consciousness as NPS 2011 nears.