sanya, The term "surfing the internet" was first used in the 1990's and has since become an idiom. However, you could use 'surf on the internet' with pretty much the same meaning. The English language is flexible like that. There can also be a slight difference in meaning To surf the Internet = to go purposely from site to site or to browse. To surf on the Internet = to browse or move from site to site randomly. Men, in general, tend to surf on the Internet for the beauty of it, to explore its limitless possibilities, and, above all, to enjoy the challenge of making it work. .net Magazine. 1995 Some parents believe that children must learn how to safely surf the Internet. ... PC Magazine I have also come across " surf IN the Internet". Surfing IN the internet would imply being deep into the net experience-- perhaps downloading files, playing games, chatting, or doing all at the same time. "I can “surf” in the Internet for hours, reading interesting articles, watching movies or chatting with pals all over the world..."

Surf the Net. I haven't heard "surfing on the Net".

Yes, always "surfing the Internet"

Actually, neither. The phrase "surfing the Web" is more correct. The 'Internet' and the 'Web' (or World Wide Web) are two different forms of technology. But don't worry; it's an extremely common mistake. The Web (software) runs on the Internet (hardware). The Web is just one of many services provided on the Internet. Probably the biggest factor which led to the confusion between the two terms is the name of the Web Browser made by Microsoft that became so popular (the dreaded "Internet Explorer"). Had they named it "Web Explorer", we most likely wouldn't have the misconception we have today. So really, if anyone is to blame, it's Microsoft!

Thank both of you!