Lexicon falls into that category of role-playing games that are really about developing worlds and settings. My beloved Microscope is another, as is the Quiet Year. It is an unusual design space in the world of role-playing games but I still believe that it falls under the larger umbrella of role-playing.
In Lexicon, each player is a scholar who is helping write an encyclopedia. At the end of the game, the encyclopedia will be made up of 26 entries, one for every letter in the alphabet.
Here is the twist, that makes the game of Lexicon one that is interconnected between all of the players. At the end of your entry, you have to cite to other entries. Indeed, at the beginning of the game they will be entries that haven't been written yet. And, you cannot write or have written an entry that you have cited.
The designer recommends that you set up a wiki to play the game, hyperlinking the citations. So, when the 26th entry has been written, the one that starts with a Z, you will have a tightly linked, self referencing document.
Honestly, this sounds so cool to me. I have really gotten a lot out of my email games of Microscope and Lexicon would take a lot of those ideas is an even more online friendly place.
And I like how, unlike in Microscope or the Quiet Year, a player can actually take on the role of a specific person. Namely a scholar or researcher who may have their own agenda and who may not think much of the other goobers who are trying to hone in on their area of specialty. You know, the other players.
BUT I have also found that keeping people involved and active in an email game can be a struggle. The commitment might be smaller, in some ways, than getting together for one four-to-six hour game but it will be a commitment that will span weeks or months.
AND Microscope has a fail safe valve in be form of periods and, in particular, events. Only a sentence or two long, they let folks make quick moves when they are strapped for time or thought. In Lexicon, every turn is a full entry and one that has to involve two other entries. That's a lot more to ask for.
For all that, I am still hoping that I manage to play a game of Lexicon in 2016. I'm certainly not going to try while I have a game of Microscope already going and some of those folks are the first ones that I would try and involve.