Referendums are simple polls where voters are asked to reply "Yes" and "No" to a simple question. In the United States, they are often called "Ballot Measure" or "Ballot Initiative".
Since almost the very beginning, referendums had been supported on this web site, but it is a telling fact that so far no single referendum poll had been created on any of the minguo.info sub-sites. Also, on a technical side, referendum implementation necessitated many special case handling, making the code more heavy and brittle. Thus, I decided to completely remove a direct support for referendums. Now, when you create a new poll, you will see one fewer option for Election Method:
However, if one wants, it is still easy to create a referendum-like poll. Simply create a Plurality poll, add the two options "Yes" and "No", and then lock the poll so that no new options can be added (or ask me to do so if you can't or don't know how to). Voilà! You'd still have a referendum poll!
For the interested parties, here are some Wikipedia references: