You guys have it all wrong.

It is the 15% VAT (value added tax) that has to be rounded up in order to collect it. The first guys comments (a penny for your thoughts) are taxed and rounded up so the next guy has to "put in his two cents."

The government has to get its cut.

Wait a minute. That doesn't work if the guy with the first thought penny is in the UK or EU and the second guy is in the US because that transaction should be VAT free, right?