Betaworks, which made a splash with its purchase of Digg last July, has made another, smaller splash today with its acquisition of the reading app Instapaper.

Instapaper allows users to save Web content they want to read later. Launched in 2008, it was an early example of a clean, reliable app that solved problems unique to mobile computing.

Instapaper developer Marco Arment announced the deal on his blog.

“Instapaper is much bigger today than I could have predicted in 2008, and it has simply grown far beyond what one person can do,” Arment said.

Arment said he had contacted Betaworks, which defines itself as “a company that builds companies,” with the offer to sell.

“We’ve structured the deal with Instapaper’s health and longevity as the top priority, with incentives to keep it going well into the future. I will continue advising the project indefinitely, while Betaworks will take over its operations, expand its staff, and develop it further,” Arment said.