I am a niche market; I need software that few people care about.
For example, I need software to dynamically manage concepts (ex: “ideas”), concept properties (“attributes”) and relationships. These products are usually marketed as “mind map” or “outliner” or (less often) concept mapping tools.
Even though this is a niche market where good software goes to die, geek developers cannot resist it. So they create beautiful products with relatively short lifespans. Past examples include Symantec’s MORE 3.1 (my all-time favorite), Ecco Professional, Lotus Agenda, Symantec’s GrandView, and Inspiration  (Mac, Windows, Palm!). There are many other examples.
Current examples include MindManager ($$$), FreeMind, Freeplane and OmniOutliner (OS X, outliner only). There are many others, the Freemind wiki has two pages describing Freemind’s alternatives.
One of those alternatives is XMind. There’s something special about XMind. XMind has been made in Shenzhen China since 2006. It’s currently available for Windows and OS X. It is the only multinational consumer-oriented Windows productivity software I’ve come across that is made in China; I don’t know of any OS X productivity software made in China.
This is an intriguing, even historic, development. 
 Didn’t exactly die, went to a school-only market.
 I don’t recommend the software though. The churn in this market and the costs of data lock mean I wouldn’t consider any product that used a proprietary file format. The XMind file format is proprietary. Even with open source products you need to evaluate the data store strategy.