Here is a website dedicated to it: http://www.hjta.org/node/320
Their explanation of Proposition 13 is:
Proposition 13 prevents property tax rate increases from exceeding 1 percent of the property's market value, and valuations from growing by more than 2% per annum unless the property was sold.
Statewide referendums are quite common in the US. Below is a link to California's 2006 propositions and results.
http://www.smartvoter.org/2006/11/07/ca/state/prop/
Here is an interesting one:
- Proposition 90. Government Acquisition, Regulation of Private Property -- State of California (Initiative Constitutional Amendment - Majority Approval Required)
Fail: 3,456,431 / 47.7% Yes votes ...... 3,790,344 / 52.3% No votes - Should the California Constitution be amended to require government to pay property owners for substantial economic losses resulting from some new laws and rules, and limit government authority to take ownership of private property?