This module provides a field type which can be used as a hotness metric or a regular view counter for entities and for much much more. In essense, entities receiving attention (views or actions defined by Rules) are heated while inactive ones slowly cool down.


Features are:

  • Views support
  • Rules support
  • Features import/export
  • Spam protection with grace
  • Memcached incident storage for high traffic sites

For basic usage information, please refer to a small introduction to Radioactivity 2.


  • Viewing a node adds energy to it
  • The energy decays at a rate defined by the half-life period. For example, a view is worth 1 energy unit at the time of clicking, 0.5 energy units after one half-life period, 0.25 energy units after two half-life periods, and so on.

Thus, by keeping the half-life period short, let's say one hour, you'll get a metric that reflects the current node view rate, or hotness. Using this metric in a view, you can create a "most viewed nodes right now" list. By setting a longer half-life, let's say 12 hours, you can setup a view that roughly reflects most viewed nodes today.

Quick start for the above case:

  1. Enable the radioactivity module.
  2. Create a new decay profile in admin/structure/radioactivity.
  3. Create a field for a content type, select a decay profile for it and set the initial energy value
  4. Create a new view for nodes, add some fields (e.g. nid, title, radioactive energy) and sort by descending radioactive energy.
  5. Create some activity and watch the view evolve.

For D6, please see the documentation for a more detailed introduction and walkthrough. You might also be interested in a walkthrough video.

Rules support

With the help of Rules module site builders are able to create systems other than generic popularity meters. You can create simple rules that raise or lower the energy level of a field on any event which the Rules module provide. For instance a simple user activity meter can be created with a few clicks.

Project Information