Marco Arment, the creator of Instapaper, posted to his blog today that the free version of Instapaper in the app store is taking an "extended vacation", but after he clearly stated his case I'd be surprised if we ever see it again. He goes on to explain that while tons of people download Instapaper Free, it's actually costs him money to support it because the ad does not generate nearly as much profit as the 70% cut he gets out of the $5 Instapaper app. His whole blog post is extremely honest and straightforward, so I'd recommend reading it. Or you could always read it later.

If you have no idea what Instapaper is, well it's a really great service that allows you to save articles online to read later when you have the time and present it in a very clean, elegant format similar to Readability. $5 is somewhat of a risk for people, but if you are into reading news or blog posts, you will probably use this app everyday like I do so I've found that the $5 is absolutely worth it.