Personally, as a GM, if my players wanted to hang out with the cool people at Jackpoint, they would need to have something to offer.
Judging from the books most of the JP users are very knowledgable in more than one area, they are often either the people describinb situations and/or locations, or they are the ones with connections to people who can do it.
So thats what I would require of my players, for FJ to want them on JP, they would need to know something of importance, and not just a single time data-dump, but a topic which would regularly be important.
In game terms, I would expert the character(s) to have a high rating in a specific (and otherwise rarely used) knowledge skill (aka, they would have to "waste" karma on it), alternatively a specialized high rating etiquette skill.
Secondly - then I could see myself expecting some sort of write-up about the subject - be it a new location not covered in SR books, a AA corporation not detailed, details about a conspiracy or anything similar.
I think most of the JP users are simply there due to connections and knowledge, and thats what I would expect from from characters wanting to join. Bring something to the table, have a lasting value to add to the usergroup.