Posterous

The company's core service was a blogging platform designed for simplicity and mobile use. Its defining feature was the ability to publish content—including text, photos, videos, and documents—simply by emailing it to a specific address. This process automatically formatted attachments for optimal display on the user's blog. The platform also facilitated lifestreaming by enabling automatic cross-posting to other social media sites like Facebook, Twitter, and Flickr. For a period, Posterous was considered a leading application for this type of integrated online activity. The business model was intended to be freemium, with plans for premium paid accounts offering advanced features for professional and business users.

In September 2011, Posterous evolved its offering with the launch of "Posterous Spaces," shifting focus toward controlled and private sharing. This update allowed users to create distinct public or private 'Spaces' for different social groups, such as family or work colleagues, with each space having its own members and settings. The update also introduced a reader tab for following public posts and enhanced its mobile applications for both iPhone and Android. By this time, the service had grown to more than 15 million monthly users.

In a move primarily seen as an 'acqui-hire' to secure its talented engineering and product team, Twitter acquired Posterous in March 2012. While the Posterous Spaces service remained operational for a period, the team was integrated into Twitter to work on key initiatives. Ultimately, Posterous announced it would shut down completely, and the service ceased operations on April 30, 2013, with users given the opportunity to back up their data. Following the shutdown, some of the original founders launched Posthaven, a similar but paid service, with a pledge never to be acquired.