Like many great inventions, Marco Arment's was born of selfish need. Mr. Arment, lead developer of the Tumblr micro-blogging platform, was discovering great web content all day at work but never had time to read it. He would bookmark it for later, but his bookmarks were a mess. And the articles he saved were often crowded with big graphics and ads, making them hard to digest. So Mr. Arment embarked on a side project to make it enjoyable to read long-form content on the web.

In August 2008 he unveiled Instapaper, a simple and lightweight app that does one thing exceedingly well. When an article piques your interest at an imperfect time, clicking Instapaper's "Read It Later" bookmark saves the article to your account, stripping away superfluous HTML formatting and graphics to surface clean, readable text. While Mr. Arment recently added Kindle integration, he said more than half of Instapaper's 400,000 users come through the iPhone App Store. In its first year, the humble app has turned a profit and landed on numerous top picks lists, like CNN Money's most useful apps of 2009 and Macworld's 20 "App Gems."

With the iPad's approach, and its much-discussed potential as a new platform for old-fashioned publications, Mr. Arment, who plans to port Instapaper to the iPad, could be providing one of a network of services needed to preserve long-form writing. "We need to work from both sides: supply and demand," he said. "I'm not a writer, so the supply side is difficult for me to do anything about. But, by making a tool to enable long-form reading on the devices and media of today, I'm hoping to increase the demand enough to influence the supply as well."

See the rest of the 2010 Creativity 50 here.