YouTube celebrated its fifth birthday on Valentine's Day. The youtube.com domain name was first registered on 2/15/2005 and the site was bought by Google 20 months later for $1.65 billion.

After the jump check out the top five YouTube videos of all time, including a terrorist, a baby and a history lesson. Have you seen them all?

You can maximize the performance of your marketing campaigns by consolidating all of them under a single ad platform. This will save time on administrative tasks, offer comprehensive analytics on campaigns across multiple channels and help you optimize them accordingly. Affiliate software is in a unique position to consolidate campaigns from across different channels because it monitors the entire acquisition process. By supporting and tracking different marketing models and offering comparative reports, the right software will provide the intelligence you need to maximize your return.

I admit it - I'm a skinflint. Call me a tightwad, a miser - I don't care. Basically, I'm cheap. And even if you're not cheap by personality, you might need to conserve cash by necessity. If that's your situation, don't despair. The Internet is tailor-made for you. Internet marketing, and search marketing in particular, is the land of the free. So step up, you skinflints, and let's see what you can do for nothing.

When I say the word "marketing," what do you think of? Probably some kind of advertising - maybe a TV commercial for Coke. That's brand marketing, and it's gotten the lion's share of attention from marketers for decades.

Far fewer people are direct marketers - the folks behind the catalogs and mail solicitations that fill our mailboxes. If you know any direct marketers, you may want to hire them to run your search marketing campaigns. Let's look at the basics of direct marketing to find out why.

Steve DiPietro is amazed at how frequently he listens to prospective clients parroting clickthrough percentages, Web traffic statistics and conversion ratios with great enthusiasm but little-to-no understanding of their value to their organizations. Increasing a conversion rate from 12 to 15 percent can become a goal unto itself as marketers immersed in number crunching can lose sight of the fact that sales aren't also growing.

Ask nearly everyone and they'll say that search engine optimization is intimidating. Search engine optimization - SEO for short - should be a familiar term and practice for anyone or any commercial company with a website. SEO is what you do to your website to get a higher ranking on search engines,particularly Google,Yahoo and MSN.The higher you rank the more likely someone will click through to your site and buy your stuff. Lately, information and tips on just how to do that can fill a library.

If baseball is the thinking person's game, then online advertising is the thinking person's medium. Much like the national pastime, part of the draw of online advertising comes from the ability to break down performance into limitless particles of useful (and useless) information, such as batting average with runners in scoring position after the 7th inning, or the clickthrough rate differential for an ad run at 8 a.m. versus 8 p.m.

As author Robert C. Gallagher observes, "Change is inevitable - except from a vending machine." And so it comes as no surprise that paid search engines are changing too. The biggest change is one of the most fundamental, affecting which paid ads are shown first in the results. The tried-and-true high bidder auctions, pioneered by Overture (later acquired by Yahoo), are being phased out in favor of hybrid auctions, introduced by Google.

How online marketers use facts, figures and forecasts.

Studies, polls, reports, surveys, statistics and forecasts. Every day the latest data on the most current trends is widely disseminated and distributed. Want to know which demographic group is most likely to spend more online, to have broadband or to download music? There's data out there that purports to have the answers.

There's no dearth of data, for sure, but just how much of this mountain of market research is useful for online marketers who need to make crucial business decisions is up for debate.

Sometimes even the simplest tasks can only be performed using the right tools. There's no point in using a chain saw when a paring knife will do the job.

These are not reviews, ratings or recommendations. It's just a collection of software, services and tools that we've come across and wanted to share with you. Here they are in no specific order.