Posterous

Posterous was a web-based blogging and lifestreaming platform launched in May 2008 and based in San Francisco. Its defining feature was email-based publishing: a user could send an email — with attachments such as photos, MP3s, documents or video links — to a single address, and the platform automatically formatted the content, created or updated a blog, and distributed the post to connected social media accounts including Twitter, Facebook and Flickr. Content could also be created through a web rich-text editor, and users could point a domain name or subdomain they owned at their Posterous site.

Additional capabilities included a built-in Google Analytics package, custom themes, static pages, comment moderation tools, and Post.ly, an in-house URL shortening service that was repositioned in January 2010 as a media sharing service able to post to Twitter. Mobile clients included the PicPosterous iPhone app (August 2009) and an Android app supporting nine phone models (January 2011). In September 2011 the company relaunched the product as Posterous Spaces, adding privacy controls intended to let users share selectively with specific groups across multiple platforms.

The email-posting design also created a security question: because return addresses can be spoofed, third parties could in principle post to another user's blog. A June 2008 TechCrunch challenge produced three successful spoofed posts, after which Posterous closed the hole; the company said it used undisclosed methods, apparently combining SPF checking and email-header filters, and did not offer a user-facing option to require confirmation for all posts.

Founding story

According to one secondary account, Sachin Agarwal and Garry Tan had known each other since 2000 as fraternity brothers at Stanford; Agarwal subsequently spent about six years as a software engineer at Apple (including the Final Cut Pro team) while Tan was an early Palantir engineer and later worked at Microsoft. Agarwal, frustrated by the friction of existing blogging tools, built a prototype that accepted content by email and published it automatically. The same account states that two consequential design choices were unintentional: routing all users through the single address post@posterous.com because Agarwal did not know how to configure per-user mail addresses, and automatically creating a blog for any sender who emailed that address without an account — both of which functioned as viral growth mechanics. Posterous was founded in 2008 in San Francisco by Agarwal, Tan and Brett Gibson, and joined Y Combinator's Summer 2008 batch. Note that source attributions of founders differ: Wikipedia names Agarwal and Tan, Y Combinator's directory lists Agarwal and Gibson, and other sources name all three.

Business model

Posterous operated a free, registration-required consumer publishing service, positioned by contemporaneous coverage among free blogging platforms alongside WordPress, Blogspot and Tumblr. The sources do not describe a paid tier or specific monetization mechanism for Posterous itself; the successor service Posthaven, built by two Posterous co-founders, is subscription-based at $5 per month.

Sources do not state a revenue model for Posterous. The platform was described as free to users and funded by venture capital and angel investment totaling roughly $10.1 million.

Traction

Y Combinator's profile cited more than 15 million monthly users, and secondary sources report roughly 15 million monthly unique visitors at the 2011 peak, up from 12 million uniques and 25 million page views in March 2010 and 30% month-over-month growth in 2009. Traffic declined to roughly 1.33 million monthly visitors by the March 2012 acquisition, and one retrospective estimates about 60,000 daily users and 52 million pages at shutdown in April 2013. A Posterous-based storytelling project, the3six5, launched in January 2010 and was nominated for a Webby Award in 2011.

Latest developments

Posterous ceased operating on April 30, 2013. Co-founders Garry Tan and Brett Gibson launched Posthaven, a $5-per-month subscription service that pledged never to accept outside funding or be sold, and offered Posterous users a migration path via the Posterous API before it was retired. Sachin Agarwal worked as a product manager at Twitter for four years after the acquisition, later joined Lyft, and is a co-founder of GrowSF; Brett Gibson is a managing partner at Initialized Capital.