Medium is an online publishing platform developed by Evan Williams, and launched in August 2012. It is owned by A Medium Corporation.  The platform is an example of social journalism, having a hybrid collection of amateur and professional people and publications, or exclusive blogs or publishers on Medium,  and is regularly regarded as a blog host.
Williams developed Medium as a way to publish writings and documents longer than Twitter's 140-character (now 280-character) maximum.
Evan Williams, Twitter co-founder and former CEO, created Medium to encourage users to create posts longer than the 140-character limit of Twitter. When it launched in 2012, Williams stated, "There's been less progress toward raising the quality of what's produced."  By April 2013, Williams reported there were 30 full-time staff working on the platform,  including a vacancy for a "Storyteller" role,  and that it was taking "98 percent" of his time.  By August, Williams reported that the site was still small, although he was still optimistic about it, saying "We are trying to make it as easy as possible for people who have thoughtful things to say". 
Medium has been focusing on optimizing the time visitors spend reading the site (1.5 million hours in March 2015), as opposed to maximizing the size of its audience.   In 2015, Williams criticized the standard web traffic metric of unique visitors as "a highly volatile and meaningless number for what we’re trying to do".  According to the company, as of May 2017, Medium.com had 60 million unique monthly readers. 
Medium maintained an editorial department staffed by professional editors and writers, had several others signed on as contractors and served as a publisher for several publications. Matter operated from Medium Headquarters in San Francisco and was nominated for a 2015 National Magazine Award.  In May 2015, Medium made deep cuts to its editorial budget forcing layoffs at dozens of publications hosted on the platform.  Several publications left the platform.
In 2016, Medium introduced advertising and gained several new publishers as customers to host their content on the platform. 
In January 2017, Williams announced that Medium was cutting its staff by 50 employees (around one third, "mostly in sales, support, and other business functions"), and closing its offices in New York and Washington, D.C.  He explained that "we had started scaling up the teams to sell and support products that were, at best, incremental improvements on the ad-driven publishing model", but that, instead, Medium was aiming for a "new [business] model for writers and creators to be rewarded, based on the value they’re creating for people".  At that time, the company had raised $134 million in investment from venture capital firms and Williams himself. 
In March 2017, Medium announced a membership program for $5 per month, offering access to "well-researched explainers, insightful perspectives, and useful knowledge with a longer shelf life", with authors being paid a flat amount per article.  Subsequently, The Ringer and the technology blog Backchannel, both Condé Nast publications, left Medium. Backchannel, which left Medium for Wired in June, said Medium was "no longer as focused on helping publications like ours profit." 
User information and features
Once an entry is posted, it can be recommended and shared by other people, in a similar manner to Twitter.  Posts can be upvoted in a similar manner to Reddit, and content can be assigned a specific theme, in the same way as Tumblr.
In August 2017, Medium replaced their Recommend button with a "clap" feature, which readers can click multiple times to signify how much they enjoyed the article. Medium announced that payment to authors will be weighted based on how many "claps" they receive. 
Medium offers users subscriptions to become a member for a monthly or yearly fee of $5 or $50, respectively. With a Medium membership, access to "exclusive content, audio narrations of popular stories, and an improved bookmark section" is enabled. 
A specific difference from Williams' earlier service, Blogger, is that posts are sorted by topic rather than writer.  The platform uses the system of "claps" (formerly "recommendations"), similar to "likes" on Facebook, to up vote the best articles and stories, called the Tag system, and divides the stories into different categories to let the audiences choose.
" Publications " on Medium are distributing hosts that carry articles and blog posts, like a newspaper or magazine. The articles published or saved on it can be assigned editors, and can be saved as drafts.
Cuepoint, Medium's music publication, is edited by Jonathan Shecter, a music industry entrepreneur and co-founder of The Source magazine. It publishes essays on artists, trends, and releases, written by Medium community contributors, major record executives, and music journalists,  including Robert Christgau, who contributed his Expert Witness capsule review column.  Medium also published a technology publication called Backchannel, edited by Steven Levy. 
Reviewing the service at its launch in 2012, The Guardian enjoyed some of the collections that had been created, particularly a collection of nostalgic photographs created by Williams.  TechCrunch's Drew Olanoff suggested the platform might have taken its name from being a "medium"-sized platform in between Twitter and full-scale blogging platforms such as Blogger. 
Lawrence Lessig welcomed the platform's affordance of Creative Commons licensing for user content,  a feature demonstrated in a Medium project with The Public Domain Review —an interactive online edition of Alice's Adventures In Wonderland, annotated by a dozen Carroll scholars, allowing free remixes of the public domain and Creative Commons licensed text and art resources, with reader-supplied commentaries and artwork.  
However, in 2013 the service suffered criticism from writers, with some confused about exactly what it is expected to provide. 
In January 2016, Medium received a take down notice from the Malaysian Communications and Multimedia Commission for one of the articles published by the Sarawak Report. The Sarawak Report had been hosting its articles on Medium since July 2015, when its own website was blocked by the Malaysian government. 
Medium's legal team responded to the commission with a request for a copy of the Malaysian Anti-Corruption Commission's official statement that the post was untrue, for information on which parts of the article were found false, and for information on whether the dispute has been raised in court. The site declined to take the content down until directed to do so by an order from a court of competent jurisdiction.  In response, on January 27, 2016, all content on Medium has been unavailable for Malaysian internet users.
The ban has been lifted as of 18 May, 2018, with MCMC stating the ban lift was because "there was no reason (to block the website)" as the 1MDB report has been made public by the government.
As of June 2017, Medium has been blocked in Egypt along with more than 60 media websites in a crackdown by the Egyptian government.  The list of blocked sites also includes Al Jazeera, The Huffington Post ' s Arabic website and Mada Masr. This is certainly not true as Medium is currently (November 13, 2018) accessible in Egypt.
Medium's initial technology stack relied on a variety of AWS services including EC2, S3, and CloudFront. Originally, it was written in Node.js and the text editor that Medium users wrote blog posts with, was based on TinyMCE.  As of 2017, the blogging platform's technology stack included AWS services, including EBS, RDS for Aurora, and Route 53, its image server was written in Go and the main app servers were still written in Node.