Indeed I do. It is described as:
an online multiplayer game played out as you travel the city with your Oyster Card. By using Oyster data we are able to show you your Tube travel, and every journey means you amass points, taking a few steps further along the way to owning London.
Chromaroma is a type of location-based top-trumps. You collect places, identities, modes of transport and passengers as you travel around the city; discover and investigate mysteries attached to different locations and build alliances with fellow passengers that share your journeys. It’s a game you can play on your own, or part of a team.
This sounds very much like a Foursquare-type version of the idea I described earlier, so I will contact the Mudlark collective to ask for more information. Hilariously, I am faced with the slightly awkward prospect of trying to express the depth of my interest, without giving the impression that I am in any way laying claim to the idea like John Turturro in Secret Window.