but that is not about IE4
However, the extend phase wasn't just IE4. They stopped piling on all sorts of non-standard vendor lock-in stuff after IE6. By the time IE7 came out, it was clear the web is here to stay.
IE6 also stuck around a lot longer than previous versions. It was released in 2001; IE7 didn't show up until 2006, and was an optional update which many users skipped.
I jumped ship when ME came out. KDE had a good browser (Konqueror), the engine of which is now known as WebKit and powers Safari. When I wasn't using Konqueror I ran NN or whatever Mozilla version they had in the day. It worked great but ran slow and was a huge memory hog.