JSON is short for Javascript Object Notation, a by now rather popular data format that is easy digestible by javascript functions (it is javascript, after all). So with JSON it is much easier to pull in data from other sources and web sites than with RSS or other XML-based formats.

Mattias Hising of Front-End Book wrote a Wordpress plugin that generates  a JSON feed from the latests posts of a Wordpress blog.  If you’re already using a Javascript library in your site then it will take only a few lines of script to include the feed your site (example code for Jquery is included in the post I linked above).

I think I will investigate if there is anything comparable for Joomla – this is such a small but useful thing.