In reply to The Lemming:
I'd argue that explicitly NOT voting is possibly the *most* effective thing you can do. Before you flame away, however, let me argue my point.
Firstly, spoiled ballots are totally ambiguous. They are not classified in any way and so the scrawls of a genuine idiot who is incapable of voting, the mistakes of those who either by ignorance or simply by accident add their signature or any other mark whatsoever to the ballot paper, the "spoiled in protest" ballots and all the others get lumped into one number: voter's intention not clear. This number is meaningless and do not believe that any politician will not play upon that fact, should the need arise.
Next, a high voter turnout supports the broken democratic system. How can one argue that the incumbent Party has no mandate for what they do when they won an election with a 78% turnout? How can one argue that first-past-the-post is a deterrent to voters if the turnout is really hight? Quite simply, one cannot.
There is no official "None of the Above" option. Spoiling a ballot is not none-of-the-above.
Not voting, however, has advantages. If the culture of democracy was such that the highly opinionated voted for the candidates they supported and those for whom no candidate presented an acceptable option simply abstained - by definition, did not express their choice - two possible outcomes realistically COULD come about.
The first would be best in my opinion: that first-past-the-post fails. If, election after election, the turnout gradually sunk, the press, the politicians and everybody would have to ask why and it is conceivable that the answer might be that people no longer support first-past-the-post. Change could then be possible.
The second would be very interesting: at the present time, the number of people disillusioned with the status quo is obscured and obfuscated. If it was blatantly clear, perhaps a new party or a new idea might come into play to try to capture these abstainees. Perhaps, just possibly, someone would say, "Hey, 60% of the people don't like the options on the ballot. What can I do that might disrupt the scenario?"
The argument that boycotting precludes one from complaining and that boycotting is somehow anti-democratic is holding democracy back. It is artificially inflating voter turnout numbers and, horrifyingly, it is also driving a tonne of people to vote out of misguided guilt or shame and not out of true preference - this is exacerbating the problem: that people vote for silly reasons, according to peer pressure, according to some "tactical" bullshit or at the very best randomly.
In the field of game theory, an auction is called "truth revealing" if the dominant strategy is to bid according to the true value one places on the item under the hammer. (Dutch flower auctions are "truth revealing", for instance). This sensationalised and emotional form of voting is NOT truth revealing because it does not reveal the true appeal, among the electorate, of the goods at hand: the consequences of electing any given party.