A few more ideas for this plugin:
a. The user can set up the plugin to do the same thing with online book, CD, and DVD stores such as Amazon, Borders, or others. The plug in searches for the proper names (it recognizes them based on their capital letters, their quotation marks, and the order of their words) and links them to the book/CD/DVD titles with the exact same names in those stores.
b. This feature can have an option for adding Associate number, if the user has one, and create a link incorporating that Associate number.
c. The feature can prioritise certain media types. For example the plugin can search and link the word "Doors" first to the find in Amazon CDs, and if it could not find the word there then it can search for it among DVDs.
d. The user can prioritise the use of Wikipedia (or any other encyclopaedia-like website) over the online stores or vise versa. So when a word such as "Robinson Crusoe" is found on a post, it can be automatically linked to Wikipedia or the book or DVD on Amazon.
e. The plugin is automatically disabled for the manually-created links, unless the user decides the plugin to overwrite his/her links.