text adventure's in the form of making money, are useless.
BatMUD, Utopia, Die2Nite etc are still profitable.
I always called these games, "Browser-based MMORPG's" though im not sure what genre they would be considered now-a-days.
PBBGs - Persistant Browser Based Games
For instance, in Archmage, you had a total of 200 turns, which you accumulated every 5 minutes (based on server). This evolved over time into the Zynga token idea. So why not simplify it and use tokens. This means you can do more with a single token compared to a 'turn.' Rather than use 20 turns to build 200 Barracks, you use 1 token to upgrade a barracks from level 1 -> level 2. (keep in mind, due to core gameplay mechanics, these things are destroyed and rebuilt over the course of the game)
Good old days. I used to play a lot of Earth, Utopia and Archmage. I am now currently making a modern innovation of browser based MUD (multi-user dungeon) using HTML5 (node.js and socket.io) because of my love for the good old days.
I think some static graphics are necessary. One of the biggest draw of Archmage for me was the strange "cult-like" images. Also, I think
1) The time/energy system. Getting x turns per hour is very very niche and IMHO needs to be replaced by something better. The fact that the most shiny example of this system is Farmville doesn't bode well for it.
The typical excuse is that this system allows "working adults" to play. I am not sure what kind of "working adults" they are referring to because I am a working adult and I am having a hard time playing because I need to be really dedicated logging in everyday just to catch up with everyone.
2) Excel spreadsheet level of complexity is not going to attract a lot of gamers.