Jetpack's built-in visitor analytics. It records page views, referring sites, search terms, and outbound link clicks, and also carries the shared visitor-tracking library used by Jetpack Instant Search and WooCommerce Analytics.
Service URL: automattic.com (opens in a new window)
tk_aip
Stores a list of anonymous visitor IDs so they can be merged into one identity once a visitor is recognized.
Up to 5 years
tk_ai
Stores a randomly-generated anonymous visitor ID so Jetpack's Tracks analytics library can link tracking events to the same visitor.
Session in wp-admin; up to 5 years on the frontend
tk_qs
Queues analytics events for Jetpack's Tracks library so none are lost if the page closes before they can be sent.
30 minutes
tk_tc
Used once per page load to work out which cookie domain the Tracks library should use, then removed as soon as it's read back.
Session (deleted immediately after use)