
Thankfully, you can disable the notifications for when a contact comes online through Skype’s settings.

How to Turn Off Notifications When a Skype Contacts Goes Online

As you’ll go to their profile to check if they’re online or wait for them to call you. Similarly, if you only sign in when you’ve arranged to call someone, the notifications are essentially useless. In either case, though, being notified about contacts coming online is unnecessary if you are leaving Skype on all the time, you likely don’t want to deal with regular notifications. As there aren’t enough people coming online for this to get particularly annoying. With a small number of contacts, this isn’t too much of a problem.

If you have enough people on your contacts list, though, you could face regular notifications of people coming online. Also, by default, Skype notifies you whenever one of your contacts comes online.
