StumbleUpon.com has changed my life. Well, okay, that’s a bit dramatic. Maybe it hasn’t changed my life, but it has certainly changed the way I look for websites – which is an activity that seems like I spend half my life doing.

Before I stumbled upon StumbleUpon, the only way to find good or relevant websites was to take your chances with a well structured search phrase through Google. But most of the best sites have come from recommendations, either through friends or through links on sites I already trust.

But now that’s all changed, thanks to StumbleUpon.

StumbleUpon isn’t a web portal, filled with zillions of links to things I might be interested in. It also isn’t a search engine where you can type in this month’s Maxim covergirl’s name. And even though StumbleUpon depends on community participation it isn’t really a social interaction community.

StumbleUpon describes itself as an “intelligent browsing tool for sharing and discovering great websites.” Which is really what it is – in a simple nutshell. And its even simpler to install and use.

Install!? Yeah, I know, I know. Calm down. This is not some memory-hogging, ActiveX-requiring, Flash-enabled, 10-minutes-to-download-at-56K, application. It’s a simple (and free) toolbar that will download and install itself to your browser and having you Stumbling within 60 seconds.

By merging the concepts of “internet browsing” and “personal recommendations”, StumbleUpon has perfected the act of searching for interesting websites by creating a nearly fool-proof browsing system. Once signed-up and toolbar installed, a user selects topics of interest, such as music, sports, health, technology, politics, etc. – with over 500 more detailed topics ranging from comic books to crochet. And that’s it. You’re ready to Stumble.

And Stumbling is fun. It’s a bit like sticking your hand in a big barrel of prizes and seeing what you pull out. Except, if you’ve set up your profile correctly, nearly everything you pull out will be of interest to you.

The toolbar consists of several items, but the most important item is the big “Stumble!” button. Just press it and Voila! – a website – that has been recommended and reviewed by others with similar interests as you – appears.

It’s something akin to channel surfing on your couch. You keep hitting the “stumble” button until something catches your eye. There are no search results to wallow through or vague descriptive hyperlinks. The system simply serves up websites that fit your personal tastes and interests.

This isn’t database “searching.” This is highly sophisticated browsing based on human recommendations. If you’re searching for samples of “Rembrandt paintings prior to 1640” than Google is your best bet. But if you’re interested in “painting” or “art history” in general, then StumbleUpon can provide some of the best sites on those subjects.

And that’s the difference. StumbleUpon isn’t for specific or targeted searching. It is for broader topical browsing. If you search for “art history” using Google, you’ll simply get search results of every site that contains the words “art history.” But with StumbleUpon, only the best sites that have already been reviewed and recommended by others will show up in your Stumbles.

Now, if you’re simply interested in using StumbleUpon to browse interest-relevant websites, than that’s fine. But you can help refine your own Stumble results, as well as help others with similar interests, by periodically rating sites you stumble upon with a simple click of the “I like it” or “not for me” buttons. By clicking these buttons, it helps the system narrow your interests by serving up sites similar to ones you like, and not delivering sites that you dislike. The more you rate sites, the smarter the system becomes for you.

I have found more interesting sites in the past month by using StumbleUpon than I have in the past 3 years without. Here are some recent Stumbles that I’ve bookmarked:

Zip Decode – At first I wasn’t sure what use this site would have, beyond just being a cool technology. But within a few days of bookmarking it, I was running an auction on Ebay when a potential buyer wanted to know if I could ship to a certain zip code. No city name. No address. Just a zip code. I immediately realized where I could find the city that matched the zip code.

Billy Harvey Music – I spent almost an hour on this indie artist’s website thanks to StumbleUpon. I laughed so hard, I nearly cried. I sent the link to a dozen friends who did the same. I’m considering buying his record, as the music is good too. I’ve never heard of Billy Harvey, and probably would have never come across this site without the help of StumbleUpon.

Mini-Putt – Okay, I’ll admit, StumbleUpon has also filled up my spare time by showing me completely addictive sites like this one. This mini-golf game has become an obsession ever since I stumbled upon it and was told that there is a way to score a perfect 18 for 18 holes. My best score currently stands at 25.

This is just a couple of samples. My list of favorite stumbles is quite long and growing daily. Here’s my StumbleUpon profile, which includes my list of favorite stumbles.

Aside from the Stumble button feature and the ratings buttons, StumbleUpon’s other features include “Stumblers” which shows people who have recently viewed your profile, as well as people with similar interests. “Groups” is a list of suggested group based on your stumbling habits. “Forum” is a collection of running discussions. “Add a comment to this page” is a one-click feature that, in addition to your “thumbs up/thumbs down” rating, allows you to make additional comments about a site. And “send to a friend” contains an address book for one-click site recommendations to all of your friends.

All of these features are for the sole purpose of enhancing your StumbleUpon experience by creating networks and connections to the best and most relevant sites on the web.

StumbleUpon wouldn't be your first choice to find a specific website. But if you enjoy the random act of discovering new and exciting content on the internet, StumbleUpon is something you should be using.