Crosslinking
Crosslinking extension can automaticly turn the text into links using pre-defined set of rules.
Instead of manually creating and changing SEO links in your entries, just define the 'key phrases' and URL they should point to - and voila! you have keyword links all around your site. Works both for channel entries and forum threads.
You can also automatically make every mention of entry titles from selected channels a link.
The replacement is done for text displayed by {exp:channel:entries} loop and for thread replies on forums. You can disable one or both of these in settings.
You can use both full and relative URLs when creating keyword-link pairs, as well as EE {path=} valiables.
The extension is looking only in text, it will keep safe the headings, image titles, existing links, javascript code etc.
You can define how many times the replacement will be made per channel entries tag in extension setting (set to 0 for no limit). You can also exclude certain parts from replacement by wrapping them into {no_crosslinking}{/no_crosslinking} tag pair.