Open Diary

Open Diary (often abbreviated as "OD") was an online diary community, an early example of social networking software. It was founded on October 22, 1997. Open Diary was shut down on February 7, 2014. The site was owned and operated by Bruce Ableson and Susan Ableson, known on the Open Diary website by the title of their diaries, The DiaryMaster and The DiaryMistress. Ableson has described Open Diary as "the first web site that brought online diary writers together into a community."

Open Diary has hosted more than five million diaries since it was founded, and was home to over half a million diaries. As of October 2008, there were over 561,000 diaries on OpenDiary.com, including diaries from 77 different countries and all 7 continents. The site innovated some key features that later became central to the architecture of other social networking and blogging sites, including reader comments and friends-only privacy.

Open Diary officially shut down on 7 February 2014 at 12:04 a.m. EST.