#Ubuntu is placing ads in its motd when you ssh in.
The way it fetches this ad is by doing
USER_AGENT="curl/$curl_ver $lsb $platform $cpu $uptime cloud_id/$cloud_id"
curl -A "$USER_AGENT" ...
In other words, Ubuntu is sending Canonical tracking information so it can serve you an ad.
This doesn't exactly run every time you log in (it caches the ad in /var/cache), but still... phoning home for a frickin ad?
Oh, great, and this whole mechanism is part of base-files. You can't just delete a package to get rid of it, since it's a core, essential package.
Hometown is adapted from Mastodon, a decentralized social network with no ads, no corporate surveillance, and ethical design.