this is an important distinction. Everything on the web is copyrighted and you can't just go and grab images/html/css/javascript without permission from the copyright holder.

And view source isn't going to show you much when looking at sites like Gmail where the code is generated by a compiler that makes it as obtuse and unreadable as machinely possible.

Exactly. Think of it like a book. You can see the source code of a book (i.e. the individual letters), but you cannot copy it (without permission)