In order to make new users feel welcome, Wikia have created the global bot, Wikia. Wherever you go in the Wikia network, you will find Wikia. Whenever a new user — either registered or anonymous — makes their first edit, they're welcomed by the bot.
Here at Tardis, registered editors get two edits from the bot: one to create their user page, and one to create their user talk page. IP users — those that haven't registered an account — get only one edit creating a user talk page.
Since Wikia welcomes each person, the edit count gives a general indicator of how many unique individuals have used the site during the time that the bot has been functioning properly. For most wikis created since late 2011, this number is much more accurate. However, for a long-running wiki like ours, it's not nearly so correct. There have been long stretches of time — the most recent being a nasty stretch in 2011 — where the bot didn't work at all.
Currently the bot claims 36,455 edits — but the bot was only brought online on 18 March 2009, and our wiki dates to late 2004. Worse, still, it went offline on 23 March 2009 and then returned over a year later on 25 April 2010 for about a month before popping offline yet again. Conveniently for a Doctor Who wiki, the anniversary of its more-or-less reliable operation is 23 November 2010 — but there have still been brief periods of interruption since then.
Also, User:Wikia can be used manually by members of Wikia Staff. Typically, they only do so to change the name of a user, so a few of the edits in the total count aren't to welcome new users.
Thus, looking at Wikia's edit count to get a sense of the total number of people who've edited here is highly problematic. But comparing the edit count in June 2013 to that of August 2013 and dividing by 1.5 will give you a pretty good idea of the number of people who've joined in that date range.
In 2017, FANDOM changed the name of this bot to FANDOM.