In addition to the traditional online forums, social media is now a place to connect with other collectors, with jersey oriented groups on Facebook. Our particular favorite is the IIHF Jerseys group on Facebook for those who specialize in national team jerseys, many of which are only available as game worn examples. It's a great place to see some very unique items and ask question of a very knowledgeable worldwide membership, which often has members posting jerseys for sale you will not find anywhere else.
Additionally, there are other groups on Facebook you can check out for game worn hockey jerseys, such as the Game Worn Hockey Jersey Collectors and Game Worn Hockey Jerseys, both of which have memberships over 1,000. Once you visit those pages, look on the right hand column for "suggested groups" to find all sorts of specialty sub-categories for collectors of just specific teams as well as equipment and collectables if that appeals to you.
Announcements and details for this and other collector meetings can be found on the forums at GameWorn.net.