Via Facebook, a pointer to an article on “The New Detective System of “Os Loucos de Lisboa””, which has an interesting mechanical innovation: crime scenes littered with coded cards for clues.
Detective scenarios use clues. Those clues are represented by cards, which can be folded in two: in the front they have a symbol (more on that later) and a description of the clue (what the character is supposed to be seeing or thinking about); in the back they have an index (a number from 0 to infinity) which identifies the clue; inside, they have a set of hypotheses.
For instance in a murder scenario, players could see a clue card which would say “fingerprint” in the front, and “#25″ in the back. Inside it could have the following hypotheses: “the fingerprint is from the murderer’s hand” and “the fingerprint is not from the murderer’s hand”.
What makes this system great, however is the interaction between clues.
That’s acheived with index-based hypotheses. Index-based hypotheses follow this format: #index -> letter. For instance: #65 -> C. In this case, “#65 -> C” means that the C (third) hypothesis of clue “#65″, whatever it is, is true.
So you can have clues that tell you that other clues are true, without telling you what they are if you haven’t found them (also letting the characters have those “we’re missing something…” conversations you see in TV shows). The down-side though is that you need to have your web of clues meticulously pre-planned beforehand - and if the characters miss one, the whole thing could fall apart (so: make the clue cards very obvious by colour-coding, so they don’t have to pixel-bitch).
While the method is focused on crime stories, you could use it for any investigative story, such as occult or scientific investigations, allowing you to have a genuine sense of unravelling mystery in games. For bulk information, you could use computer support (so have the card contain a password to a file). Or, if you want people to spend some time “processing” the clue, or give information to some people but not others, you can use simple encryption (e.g. clues of a certain type are Caesar ciphered, with the relevant character knowing the key).