It converts strings of normal ASCII characters into Unicode characters that look similar. A primary use might be to hide email addresses from spam bots. It might also come in handy in any other situation where text needs to be human-readable but not computer readable (maybe for use with a CAPTCHA of some sort?).
It also functions as a leet speak translator for those who are into that sort of thing.
Credit for the idea comes from this post: http://lkozma.net/blog/random-web-ideas/
The author says he got the idea from this Stack Overflow rant: http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454
Any feedback would be greatly appreciated.