Communism is not about taxation though. It is about the end of exploitation of people by other people. And any collaborative initiatives are communist (or perhaps Marxist?). :-) As long as people aren't being forced by well, force or cirumstances to agree to stuff.
I have no idea why everyone equates communism with taxation.
The only known implementation used taxes, but they were trying to get rid of the money altogether, as well as the state. Didn't work out in the end though.
Anarchism is sometimes (a lot of times) a kind of communism.
To wuote wikipedia:
Communism is a specific stage of socioeconomic development predicated upon a superabundance of material wealth, which is postulated to arise from advances in production technology and corresponding changes in the social relations of production. This would allow for distribution based on need and social relations based on freely-associated individuals.
The term "communist society" should be distinguished from the Western concept of the "communist state", the latter referring to a state ruled by a party which professes a variation of Marxism–Leninism.