Use a search engine.
With a lot of tips and tutorials in html format you might look at Sleuthhound at
http://www.isleuthhound.com/products/. This program lets you specify search areas (i.e. store your files in folders called Tips or Tutorials) then you can use Sleuthhound to search for key words just like a search engine (Google, AltaVista).
For example you could search for "layer mask" or "brushes" etc. and Sleuthhound will find and display all the files it found with those key words, complete with a header and some of the text from the file.
It supports Boolean and wild card searches and there's a free demo download. The regular program costs $20.00 US and the Pro version is $34.95
Ron