Littlesnitch informs you of when anything makes a connection to or from your computer, tells you which service is doing it, offers some information (& even pinpoints the connection on a map), and asks you if you'd like to allow it, block it, just this once, or until the app you're using quits, or forever. When you first install it you'll be amazed at how many things are making connections to & from your machine, and you'll have some looking up to do, to figure them out. Often times if I'm unsure, I'll block them until quit, then if the site or service stops working, I quit the app, and the next time it runs, I know to allow it, and can then set it to forever. You can then review the big list of rules you're creating to see if you accidentally blocked or allowed something you'd rather not. So all the privacy threats and trackers, DOA. Any malware tries doing anything and you know immediately. Any software of illegitimate origin, you'll see it misbehaving before it can. It's quite nice.