See {T303995} for context.
We're aiming to answer questions about blocked account creation like the ones listed below. This list is not exhaustive and we'll likely add/edit it along the way.
# What countries are more likely to be blocked? (One idea is to relate blocked account creation attempts to page views in order to identify higher-than-expected likelihood of being blocked?)
# What kind of blocks (local/global, short-/long-term) are more frequently encountered?
# To what extent are we blocking bot account generation? (e.g. frequent block encounters by same IP & user agent)
Whenever an anonymous user visits Special:CreateAccount and is denied access with a block message, log an event
In scope:
* local IP blocks
* local autoblocks
* global IP blocks
Not in scope:
* other methods of denying account creation (AbuseFilter, DNS blacklist, TOR blocking, throttling...)
Event details:
* block type
* block ID
* user IP
* user agent
* API or special page (if we instrument the API as well)
* platform (desktop/mobile if special page, might be combined with the previous one as a `platform` field with API/desktop/mobile if that makes sense)