If you still haven't answered Web 2.0's knock on your door, maybe a little game of tag will help get you up to speed.

Tagging is part of the online phenomenon that has birthed social bookmarking sites like Del.icio.us, as well as given photo-sharing sites like Flickr more search engine relevancy.

If you're not aware of either site, you probably know somebody who's intimately familiar with them, as Yahoo! (NASDAQ:YHOO) bought up both upstarts last year.

Tagging started out as a simple way to get things organized. If you want to find a nice snapshot of a sunset on Flickr, entering the word "sunset" in the search box is the logical way to start. You can browse through more than 850,000 sunset-related photographs until you find the perfect rainbow sherbet sky.

Before tagging, you had to rely on descriptions provided by the person uploading the digital picture. Unfortunately, even master shutterbugs can get sloppy, especially when they're uploading dozens of snapshots at the same time. That's where tagging comes into play, as the uploader or anyone else in the community can submit descriptive tags to help out the search process.

If it weren't for tagging, you'd probably have never found sunset photos with incomplete captions like thelostballon or Dubai 09-06 (226).

Beyond the digital camera
A picture is worth a thousand words, but a dozen tags will do just fine.

Identifying the content of graphic images is a bounty for paid search specialists like Yahoo! and Google (NASDAQ:GOOG), because that allows them the luxury of serving up perfectly targeted ads on those pages.

The quest to cull relevant data from an editorially unseen photograph drove Google to acquire Neven Vision last month. Expect similar deals in the future, as larger players warm up to promising upstarts that automate identification technology.

Naturally, tagging is also gaining traction in video. Booming sites like YouTube and News Corp.'s (NYSE:NWS) MySpace rely on tagging to help fuel the search results of their video streams.

However, tagging isn't just for eye candy. Blog sites and social networking hangouts have also taken to tags so readers can quickly identify pages that will appeal to their preferences. Whether you fancy a particular football team, musical genre, or aspiring politician, the art of tagging in perfect execution can enrich your cybersurfing experience by sparing you from wasted time.

Turning tagging into bagging
So, what does this mean for you as an investor? Let's take a field trip through our new beta service, Motley Fool CAPS, to see the power of tags in action. Let's go with Microsoft (NASDAQ:MSFT) as our guinea pig stock.

There are over a dozen tags listed on CAPS under Microsoft. Some are obvious, like "Application Software" and "S&P 500," but a few may pique your interest, like "Disrupts Bricks-and-Mortars" and "Products for Nerds."

Click on the nerd tag, and you can get in touch with your inner geek as you see Microsoft listed alongside a half-dozen other stocks like TechRepublic.com parent CNET Networks (NASDAQ:CNET) and scientific calculator specialist Texas Instruments (NYSE:TXN).

As a bonus, check the top right of any tag page and you'll see how that basket of stocks has performed yesterday, over the past month, and over the past year.

Many publications will break up how sectors have been faring, but you'll be hard-pressed to find a second source that will let you know that the "Products for Nerds" providers have averaged a 9% gain over the past 30 days.

You don't have to stop after one tag. Digging into one tag will open up new possibilities, and you can keep swinging like Tarzan or Jane going from vine to vine until you get to your desired destination. If you keep seeing the same names creeping up again and again, there may be a stock there that's right up your alley. If you happen to stumble upon an unfamiliar company or an unlikely one, do yourself a favor and take a closer look. There may be more there than meets the eye.

Tagging can open up your pool and widen your watch list. It may even find you prioritizing your next buy or sell decision. It's like stock ideas in concentrated form: All you need to do is add the due diligence.

So, what are you waiting for? Tag, my friend. You're it.

Motley Fool CAPS is a FREE new community-driven experience where individual investors pool their knowledge to seek out stock ideas. Are you up for the challenge? Go ahead and give it a shot .

CNET Networks is a Rule Breakers newsletter recommendation. Microsoft is an Inside Value selection.

Longtime Fool contributor Rick Munarriz believes in taking chances to earn superior returns. He does not own shares in any of the companies in this story. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy .