Regular suspensions (issued by site moderators) usually last 7, 30 or 365 days, depending on how severe the offense was and the user's history. See A Day in the Penalty Box; this also includes some common reasons for suspensions.
However, this user has received a network-wide suspension from the site owners, and those can last longer:
What is a network-wide suspension?
A network-wide suspension is applied to all network accounts of a user. It can only be issued by Stack Exchange employees and can be longer than 365 days. The most common reasons for a network-wide suspension are spamming, trolling, and to cool down.
(source: the FAQ on Meta Stack Exchange)
Do anybody thinks that it's worthy or important to create a system set up which will generate some automated messages that will warn the users from doing such things or to acknowledge the moderator on this type of activities?
If it's just a minor offense, the moderators will usually first issue a warning instead of suspending. So that system is already in place.