actually, if you know my IP you can use a number of programs or just a classic terminal to check my open ports and, if any are found, you can try to sneak your way in as a "client to the service the port usually provides"
example if I'm hosting a TeamSpeak server, you'll know I have a serverquery set on it as well probably on the default port, so if you see a port in the 'serverquery' range open, you can try, if I'm an ***** and don't change passwords or make an 'admin' 'admin' account... you can basically hack my teamspeak like that... and that could technically be called hacking my computer... even tho it's not the webcam functionality mentioned by original poster