TheAgencyStar gaming group has been going strong for 4 years now and we are in our 4th Season of play, backstories and such. We have a core group of players which consists of 8 of us with a bunch of other members we play with here and there at other stores and conventions. I think the biggest reason we have stayed together for so long is the fact that we use the Spycraft Agency Database 2.0, which leads me to your second question. The SAD 2.0 is an Access database that you can use to create files for your missions, like Mission Reports, Identity and Organization Reports and so on. Once you create them on the GC side of the database, you can use it during Intel for your players to actually log into the database and pull up all the mission related reports and files, kind of like you see in the movies and what not. We actually connect a laptop to a projector and projector screen and do our Intel in one night. Makes for more of a "Get together" to kick off a new mission.
Each Mission is designed mainly for the use of the SAD 2.0 which is a .exe file that auto loads all the mission's data into the GC side of the SAD 2.0, but as of late we also provided just the Audio and Mission PDF file from the .exe file as a Mission Bundle download - No SAD 2.0 needed for those that do not have Microsoft Access.
Players can either pick which format they want to use. .exe download to be used with the SAD 2.0, or the Mission Bundle .zip file consisting of .mp3 audio and .pdf file (No SAD 2.0 required)
TheAgencyStar has catagorized all of our missions into a Main missions (more than one night of gaming), Mini-Mission (1 possibly 2 nights of gaming), PBP missions (Play-by-Post mission intended to be played in a forum) and the latest is the DOTB mission (a yearly run mission centered around "The Triggerman" that contains ONLY a .mp3 audio and .pdf mission file)
Hope that answers your questions.