2008

2009

• 11 Aug - Earliest known (and still existing) categories created: Category:18th Century American Immigration and Category:Italians in Sweden.

2010

• 2 Feb - First Official WikiTree page (/wiki/Categories) was created in order to help explain categories and categorization.
  • Category:Categories was created to serve as the top level category for all other categories to be placed into.
  • Rapid category expansion took place, including regional categories

2011

2012

• 26 May - First discussion in G2G surrounding 'Personal use of categories', which later lead to the creation of Personal Categories.
• 28 Jun - Chris Whitten Created the Categorization Project page. Lianne Lavoie was an early member and worked on building the page.

2013

• 26 September - First Categorization google group post.
• 21 December - There is discussion within the Categorization google group about the use of languages in categories.
  • English speakers can use English named categories. German speakers can use German named categories. Italian speakers can use Italian named categories. We don't have a category limit. The need (participation) should drive the category. If we get hundreds/thousands of Germans, Italians, Welsh, etc they can make categories in their native language to be read by them. They should be encouraged to link to the same category in other languages. But the primary focus should always, always be on being USEABLE. We can't expect German people to know English or French or Spanish. It is enough they can communicate in their own language.Gail Cox

2014

• 13 Mar - Co-leaders introduced: Phil Smith, Daniel Thompson and Terri Rick
• 8 Apr - Gail Cox added as co-leader, total of 4 co-leaders
• 1 Jul 2014 - Terri Rick departs as leader, leaving 3 co-leaders

2015

• 15 Jan - Phil Smith departs as co-leader; project has 2 leaders
• 28 Apr 2015 - Daniel Thompson and Gail Cox depart as leaders; project without leader.
• 31 Dec 2015 - The project added 2 leaders: Maryann Hurt and Abby Glann.

2016

2017

• 14 Mar - Maryann Hurt departs as leader.
• 7 May - Template:Top Level was created. When placed on a category, it provides a visual warning to users that the category should not hold profiles, and that profiles should instead be added to lower-level subcategories.
• June - WikiTree Team Member Aleš Trtnik sets an automated program, Editbot, to perform automatic renames, merges, and deletions of categories.
• July - Aleš Trtnik developing Category Info Box for use on category pages
• 31 October - Jamie Nelson became a leader of the project.
• 1 November - Natalie Trott became a leader of the project; Abby departs as leader.

2018

• Project revamped to include teams for maintenance and vision and collaboration. Goals and mission of project defined.
• June - Jamie Nelson stepped down as leader.
• 8 Jun
  • Added a feature to profiles where a warning will appear on Save for categories that do not yet exist.
  • Category Selector added to profiles, where you can search for categories and have them automatically added to profiles.
• July - Category error report first introduced.
• November - Steve Harris became a leader of the project.

2019

• 9 Jan - Categories containing the Top Level template are excluded from the Category Drop Down list.
• Feb - Amy Gilpin became team leader for content errors maintenance team.
• 9 April
  • Categories now display at the bottom of profile pages.
  • Category request form added to WikiTree. Members could now request a new category directly to the project.

2020

• June - Isabelle Martin added as leader, bringing leader total to 3.