Ah, good old Netscape. With its hardcoded buttons going to hardcoded URLs to give you a starting point for "surfing" the World Wide Web. And the "throbber"... they could have put up the system's hourglass cursor, but they used the throbber animation to signal to the user that the network, not the machine itself, was busy. UIs had a much clearer vocabulary back then, the money was in the user having situational awareness and making informed decisions about what to do, not in blind "engagement".