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_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)
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
Valerie, I was so glad to hear from you! According to my blog, you hadn't posted anything new for 3 months! So, imagine my surprise to come to your blog and see this wonderful stuff. Trust me, I will come by often, even if Blogger tells me that you are not posting! Now, I have to go back and see what else I have missed!
xoxo
Nancy