Liquid's Filters and Links Package Modules

You may consider using the Links Package (http://drupal.org/node/24719) along with your filter.

Senario: If Links.module installed manage ExternalLinks (replaceFreeExternalLinks(), replaceExternalLinks() in mw_parser.inc) in a way that leverages its capabilities.

Advantages:
- An API for managing URLs in a generic way
- A main links.module that governs the behavior of the Links Package's global features
- A links_related.module which allows the administrator to add a link field to any desired node types in the system
- A links_weblink.module which defines a node type of 'weblink'

External Link management is always a challenge for wikis, as many wiki platforms bind the links to the text of the wiki.

Issues:
Age: dead links need to be managed as the document ages.
Link Spam: enable global deletion or rerouting of link spam
Tracking: provide explicit tracking of network of external sites
NoFollow and Redirect: Add nofollow parameters lowers the value of link spamming a site. Use of a Redirect, into a tracker allows for early identification of link spam abuses.

Negatives:
Development: Links Package is still under development. You may wish to wait for the set of modules to stabilize.
Management of large links sets: The package still needs to go through some iterations in its management of large numbers (thousands to millions) of external links.

Thx - James