Will prime number be a good bitcoin replacement? Bitcoin has a hard limit, which is not really how money works. Prime number seems to be ever increasing and hard to farm too.

hmm, to use a NoSQL to avoid JOIN? A RDBMS can be designed to avoid joins easily with flat tables or text columns. So far, the only values I see from noSQL solutions is to sacrifice ACID for horizontal scalability to fit the user scenarios where ACID is not that critical. Everything else can be covered by RDBMS easily.

"Fashion" -- this reminds me that in the fashion industry, a particular fashion is copyright-able, but not patentable. I think user interface should go the same way.

Can 5 free cells solve all FreeCell puzzles, just like 4 colors covers all maps?