RealPlayer was a lousy plugin but the video codec was pretty good. People used it to distribute bootleg TV series and movies before the introduction of Divx. It was especially popular with anime fans. Java applets were pretty much always terrible, but the the real cancer of the era was ActiveX imho. It was a security nightmare.

I was a (very) young man when Flash was born (it was called Shockwave then) and now here I am, witnessing its death. Not that it will be missed that much, it was considered bloated, slow and buggy even in the early 2000s. Still, it's a piece of internet history. RIP