Last week the Editor Engagement Experiments team deployed a new extension to all wikis, Extension:Campaigns (http://www.mediawiki.org/wiki/Extension:Campaigns). 

The campaigns extension does one thing: if you add "campaign=example" to a link pointing at the account creation form, it logs the campaign name at the time of signup. 

This capability has been around a long time in some form or another, but we disabled it so we could get to work on our redesign of account creation and login. Now that's it's finished, we wanted to make it available again. 

There's more in the documentation I linked to above, but the general point is that this gives us a low cost, minimally invasive way to figure out how many people are coming to sign up via a particular avenue. 

Among our first test cases, my team would really like to know if significant numbers of people are signing up via the links English Wikipedia puts in system messages directed at those viewing semi-protected pages and anonymous editors. I've put up a proposal about this on-wiki at https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(proposals)#Let.27s_figure_out_a_little_bit_more_about_how_new_editors_are_signing_up

If you have any questions about how campaigns work and how they might be applied elsewhere, please speak up. :) 

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