He said the success was based on the user's sense of accomplishment, being able to upload a video she wanted to show people. Sharing. It all started, he said, when two people wanted to post videos of a wedding for the other guests. Ah! I stand corrected. This interaction engineer (sorry, I missed his name) was talking about the user's set of tasks. I don't know if they have a mental model drawn that depicts the things a user wants to accomplish, but it certainly exists in their minds. And they designed YouTube to support these tasks. Success.

Which reminds me of another question I was asked yesterday. "What makes an online product successful?" Beyond the "right place at the right time" phenomenon, I think there are two components: desire and heart. It is easy for us in the industry to get excited about a cool product idea that uses the technology in a new way. But it's been demonstrated time and again that "cool" and "new" don't necessarily make a marketable product. And because of that word, marketable, analysts tend to talk about how businesses didn't do the right amount of market research. I like to look at it from a different perspective (because you can't predict how much market share the next crazy killer app will have). There has to be the desire to accomplish something. A person walking down the hallway to their computer will have several things on her mind. There is some pre-existing need, a wish to achieve something. Take, for example, the popularity of emailing files. Despite the fact that it's not secure, businesses sanction it. Why? There is a desire to make more room in the day for real work, rather than spend time logging on to an ftp server or uploading to a tool like Basecamp. There is the wish to prod someone to look at a draft "real quick." There is the need to send someone a report right now, so the two of you can go over it on the phone as you speak, rather than putting it off. It's compelling. People use tools because they fill a need they've already been thinking about, at least obliquely.

The other part of the successful online product equation is heart. I mentioned this before, and it was a topic of conversation at UX Week. A product has to be fun to use, be intriquing, have a human touch. Sure, there are plenty of products which are successful but don't have much heart. Say Excel, for example. There's a Long Tail opportunity, for sure. Think of all the versions of a spreadsheet that could be specific to a certain trade. What about engaging ways you could help a purchasing agent compare prices of similar products between vendors? You could have property importance sliders and price history graphs. You could do it in Excel, but it takes skill and time. Who wants to do that if you could just buy it? An application made by a human who has deeply studied my trade and knows what will really make my job go faster? No doubt! Easy decision.

So, desire means a person will use the product; heart means a person will keep using it. Together, desire and heart make a great product. And, hoo boy, is YouTube ever addictive.