I think you have to create a module adapted to each situation. I made a module for Joomla Sites which can then easily install a "pligg-it" button sending any article to your pligg site. I used a "digg-it" module and hacked it to be used with pligg. The same can be done with Wordpress and many other
cms systems.
You can download and adapt my Joomla module to your needs, make your own module and propose it to the huge and active Joomla! community.
A a pligg-it button for Joomla sites publishing on the pligg bruxello.com