How to Categorize a K2 Item to Multiple Categories in Joomla Using Extensions and Plugins
Common problem for K2 in Joomla is categorizing a K2 item in multiple categories or more than one category selections. To date, K2 only allows a single selection categorization. There are fixes and solutions which hacks the K2 core files, which is scary and not recommendable as this can break your website, or K2 functionality, and updates will only override these hack changes.
Below are some extensions and plug-ins that works well with K2 for tagging an item to multiple categories.If you have additional finds, please feel free to notify us.
Free K2 Plugin
Additional Categories for K2 (by Netpin)
Paid / Commercial Extensions / K2 Plugins
Multiple categories update for K2 version 2.6.9 (by DVLancer)
Inceptive Multiple Categories for K2 (by Inceptive Design Labs)
K2 Multi Categories (by US Joomla Pro)
(available to date up to Joomla version 2.5)