I don't know about all the changes, but one of them is the fact that they were one drawn by hand and today by computer.
Anime Network was created in 2002.
Anime UK was created in 1991.
Mega-Anime was created in 2005.
Anime Insider was created in 2001.
Firestorm - anime - was created in 2002.
Bismark - anime - was created in 1984.
Anime Central was created in 1998.
Anime Candide was created in 1920-10.
Anime on Demand was created in 2011-04.
anime was created in Japan
Astro Boy was the first anime to be created. It was created by Osama Tezuka.
Anime Sound Production was created in 1976.