The communes you speak of were largely a subset of the "flower power" hippy communes of the sixties and early seventies in the US, and indeed as you say, often in California.

One facet of the youth movement was a disaffected, apolitical counterculture, made up of people who were known as hippies. These young people decried materialism, mocked convention, spurned authority, joined communes, enjoyed rock music, and experimented with drugs and sex. Often hippies asserted their rebellious attitude through elements of personal style, such as long hair and tie-dyed clothes. 
Microsoft's Online Encarta Encyclopaedia

Heinlein himself doesn't appear to have taken the book terribly seriously, but his concepts radically shaped and influenced the new thought processes emerging in the 1960s. The novel entered mass consciousness like a firecracker, predicting and describing so much of the upheaval that was to come. The flower children dug it so much that they founded many small communities with names like "The Church of All Worlds" and "The Mithril Star" around Smith's water-sharing culture of free love. "Grok" even made it into most dictionaries.
http://www.space.com/sciencefiction/stranger_appreciation_991101.html

Robert Heinlein's Stranger in a Strange Land became a hip literary favorite, and in due course communes devoted to its ideas emerged, including Sunrise Hill in western Massachusetts. 
http://www.thefarm.org/lifestyle/root2.html

Stranger in a Strange Land inspired a branch of the modern pagan movement (neopaganism) that is still active today - The Church of All Worlds ( http://www.caw.org ), which is even a legally recognised religion in US. The Farm ( http://www.thefarm.org ) is an example of a commune based on such a philosophy which is still in existence today.