Less Wrong is a community resource devoted to refining the art of human rationality, sometimes known as rationalism. It has undergone a rise and arguably a fall in recent years.
LessWrong developed from Overcoming Bias, an earlier group blog focused on human rationality, which began in November 2006, with artificial intelligence theorist Eliezer Yudkowsky and economist Robin Hanson as the principal contributors.
In February 2009, Yudkowsky's posts were used as the seed material to create the community blog LessWrong, and Overcoming Bias became Hanson's personal blog.
The site's use of Reddit-style voting and materials lead to significant growth and interest over the following years.
At some point Eliezer Yudkowsky finished writing the sequences.
During this period, popular fan-fiction HPMOR was started and finished.
Around 2013, many core members of the community stopped posting on Less Wrong, because of both increased growth of the Bay Area physical community and increased demands and opportunities from other projects. MIRI's support base grew to the point where Eliezer could focus on math research instead of community-building, CFAR worked on development of new rationality techniques and rationality education mostly offline, and prominent writers left to their own blogs where they could develop their own voice without asking if it was within the bounds of Less Wrong.
As of 2016 the community is far less vibrant than it once was. The forum's karmic barrier to entry stands, but submissions are down. The wiki has low traction and it is potentially in need to streamlining around remaining activity rather than its former glories.