Last week, as an experiment, we decreased the cost of posting from 10¢ to zero. In its place, we now require that for any post to actually show up on the "hot" page it must receive at least one payment. The primary motivating factor for this was to decrease the burden of posting for new users. It is now possible for users to earn their way in by posting high quality content *without* already having any money.
The original motivation for the 10¢ cost was to decrease spam (some users posted hundreds of posts containing no content filling up the "new" and "hot" page). While it was successful at decreasing spam, we are worried it was too big of a barrier to new users. So we're going to try keeping the cost at zero for a while an explore other mechanisms to decrease spam.