Why does my ssh login include what looks like a promotion for a TechRepublic article?

In this file:

/etc/pam.d/sshd

Comment out the following 2 lines:

# session    optional     pam_motd.so motd=/run/motd.dynamic
# session    optional     pam_motd.so noupdate

This should remove the MOTD.

Another approach is to specify ENABLED=0 in the config file /etc/default/motd-news. This may be preferred, based on a review of /etc/update-motd.d/50-motd-news:

$ grep -A5 Source /etc/update-motd.d/50-motd-news
# Source the local configuration
[ -r /etc/default/motd-news ] && . /etc/default/motd-news

# Exit immediately, unless we're enabled
# This makes this script very easy to disable in /etc/default/motd-news configuration
[ "$ENABLED" = "1" ] || exit 0

You can update /etc/default/motd-news in your editor of choice, or use sed or perl. Note that root privileges are required:

sudo sed -i -e 's/ENABLED=1/ENABLED=0/' /etc/default/motd-news

The link to the TechRepublic article is coming from the output of this script, which is executed for each login:

/etc/update-motd.d/50-motd-news

You can disable just that script by removing execution permissions:

sudo chmod -x /etc/update-motd.d/50-motd-news