OS X didn't ask for admin password

I'm hoping for a little insight...So today I installed Skype on my MBP and after the installation was complete I realized that it never asked for my administrator password. Does anyone have any ideas about why this happened (or didn't happen)?

You were not asked for your admin password any time during the process of un packaging and moving it to Applications?

that's correct...it never asked for password

You may not need to enter it if you're user has administrator privileges. I rarely get asked for admin privileges when moving files in and out of /Applications (once in a while I will but I suspect that is because of the privileges on particular files).

Is your user the admin on your machine?

Installing an application with the admin account doesn't actually prompt you for your password unless that application is trying to access system files, either to embed itself or modify existing files. Applications and the system are fairly well quarantined in OS X, so if you are already the admin account, then it will only prompt you in situations where your action would modify system files.

Thanks for the clarification. That explains it because I was logged on as admin. I appreciate the help.

Any time. Some programs do require access to the system's file structure, especially Adobe apps, but for the most part, they won't.