In today's New York Times Magazine column "Why Vote?", Freakonomics authors Dubner and Levitt argue that it is not rational to vote.
Basically, because the act of voting exacts a cost on the citizen, and because their is virtually no observed benefit in terms of affecting the outcome of the election [they cite research in which mroe htan 40,000 elections were examined, comprising nearly 1 billion votes, with only 7 elections being decided by a single vote] one can discern that the costs outweigh the benefits.
Research by Patricia Funk on voting behavior in Switzerland finds that when voting became virtually costless (mail-in votes) people actually participated less. The author speculates that people voted only due to the percevied social gains: social esteem, benefits from being perceived as a cooperator or just he avoidance of informal sanctions.
Clearly this has implications for the possibility of internet voting.
I wonder what these conclusions imply for ethical behavior more generally. A friend of mine once said that her ethics were based on the question "what would happen if EVERYONE made the choice to do X?" If she could conclude that everyone doing X was a good thing, then she would go ahead and do it. If not, she would avoid the behavior. One obvious example is the defenestration of ciggy butts. If everyone did this, our streets would look like ash trays. So, even though your marginal contribution is negligible, by these ethics, you should still not throw it out the window.
Economic rationality, on the other hand, would argue that the marginal cost to society is smaller than the marginal gain to the individual (in terms of decreased cost of personal clean up).
No wonder they call it the dismal science.