Right, but Skype has an auto sign in feature for windows too. You can close it so it's not in the taskbar and only appears in the system tray, but it's still signed in, and you can still get calls.
I really don't see that as a disadvantage!
Anyways does skype stay sign in after you close the app on ios, android, and windows phone? Or it has a period of time like yahoo messenger and others before you have to click on the app to open it again!