There is more to Internet searching than HTML files. There exist more than a few Internet services offering the ability to search newsgroup posting. There are fewer services allowing you to search mailing list archives.
Regular expressions are a way to describing the shape of words as opposed to their meaning.
Regular expressions are also used the infamous grep program of Unix computers. Used effectively, grep can locate information lost on just about any file on your file system. The time spent learning regular expression syntax is not time lost. You might also consider creating your own search engine. There exist quite a number of these tools.