Netbooks achieve, in a larger form factor, nothing more than an iPhone or other modern smartphone.
Whenever I see someone make that claim, I think to myself "On what planet are those people living on?".
Netbooks are fully functional computers that run full-blown OS'es. Smartphones do not. Have you ever tried to do any word-processing on a phone? have you tried running spreadsheets? Have you tried doing anything that resembles data-entry? Have you tried plugging USB-stick to a phone? Have you tried doing image-manipulation on a phone? Hell, have you tried opening URL's in new tabs in iPhone? I bet your answer to all of those is a big fat "no".
Netbooks can run any apps that you can run on a normal computer, smartphones can not. Hell, you could do 3D-rendering on a netbook if you wanted to! To claim that "iPhone can do anything a netbook can do" is 100% false.