In Exchange, you can have multiple folders that contain contacts. I asked our Exchange guys, who said that over about 5,000 you may run into issues. YMMV. I ha

In Exchange, you can have multiple folders that contain contacts. I asked our Exchange guys, who said that over about 5,000 you may run into issues. YMMV. I haven't worked in a Congressional office, but if you're keeping track of constituent corespondents with Exchange contacts associated with individual users, your system is going to break down well before 10,000 users.