Earlier this year we supported the IxDA in launching a new version of their IxDA.org site. One of the many interesting new features of this site is the ability to sort content by "hotness". The goal of this tool is to create a list of interesting content on the site. Their analytics show them that most people who are involved in the site visit it at least twice a month. So, they wanted a system to highlight content over the last two to three weeks. Enter the radioactivity module.
Radioactivity Module for Drupal
The Radioactivity module works on the concept of adding energy to a piece of content which then "decays" (or diminishes) with a particular half-life. The exact behavior is up to the site administrator, but on IxDA.org we originally set it up with values roughly similar to:
- Posting content adds a lot of energy so that the hotness favors recent items.
- Commenting on a post adds some energy
- Voting up adds a bit of energy, voting down subtracts some energy
- Favoriting a post adds some energy as well
We've got a few other elements that affect energy to help offset any potential gaming.
We set the half-life for decay to 15 days. So, if a piece of content gets posted and 3 comments and 2 vote ups and 1 favorite with 100 views on the first day it will have about 500 units of energy. If it gets no new energy, it would decay down to 250 units of energy after 15 days, and then down to 125 after 30 days and so on. Eventually the energy and decay are really small and for efficiency the module simply deletes all records with less than 2 units of energy.
