I happened to find this website quite by chance. From their introduction page:
Seasteading means to create permanent dwellings on the ocean – homesteading the high seas. A seastead, like in the picture above, is a structure meant for permanent occupation on the ocean
Currently, it is very difficult to experiment with alternative social systems on a small scale. Countries are so enormous that it is hard for an individual to make much difference. Seasteaders believe that government shouldn’t be like the cellphone or operating system industries, with few choices and high customer-lock-in. Instead, they envision something more like web 2.0, where many small governments serve many niche markets, a dynamic system where small groups experiment, and everyone copies what works, discards what doesn’t, and remixes the remainder to try again.