This summary is not the rule. The rule text controls.
If you file a complaint but never manage to serve the other party, your case can get thrown out after a year. This rule lets the judge dismiss cases that have been sitting around without being served on the defendant. The one-year clock starts on the date you originally filed the complaint.
The good news is that this type of dismissal is "without prejudice." That means you're not completely out of luck. You can still file the case again later if you need to, as long as you're within any other deadlines that might apply (like a statute of limitations).
If the judge dismisses your case under this rule, the court has to mail you written notice. They'll send it to whatever address you gave the court when you filed the case. So it's important to make sure the court always has your current address, especially if you move while your case is pending.