How is the internet harmful?

It's had both bad and good effects.

Bad:

-it's dangerous: cyber stalking, etc.

-it's bad for us: people spend hours staring at the screen instead of outside. The result is eye strain, headaches, obesity...

-spelling, grammar, etc. is ignored on the internet and proper English is dying out

Good:

-we can keep in touch through email, forums, etc. with people from around the world

-information such as news is instantly available at the touch of a button

-it's useful for research, checking our stocks online, booking flights, etc.

-it's oh so convenient, allowing us to shop at home, check bank balances without going out, etc.

In general, the effect on society has been largely good. However, many associated problems such as the lack of quality control and technology's stranglehold on everything have compensated for the good effects.