The bad of internet communication is that it can be irresponsible, cruel, and frivolous.
It is irresponsible because the commenter runs no risk. He or she does not undertake to fix a problem. He can say “Mrs. Doubtfire sucks” without having the responsibility of making a movie better than it and having it come in on budget, to give an easy example.
It is cruel because the commenter is able to give vent to his sadistic impulses and envy. He can salve his wounded self-love by causing pain.
It is frivolous because the poster or commenter or troll can assume identities and facts at will.
Needless to say these three qualities enforce each other. Because the poster runs no risk he need not fear punishment if he fails to be kind. Because the identity is shifting and anonymous it can be irresponsible. Because the poster lacks a sense of personal power he is touchy and easily wounded and often cruel.
Each of these is the bad form of a good trait.
A person who is irresponsible is also footloose and fancy-free. He or she is able to be honest without having to worry about the real life ramifications of his or her honesty.
The cruel person is able to be open about dark, sadistic impulses. If he or she thinks Mrs. Doubtfire is garbage he or she can provide honest feedback and need not pussyfoot around.
The frivolous poster is able to be playful and explore different possibilities.
If you receive feedback on the internet that is cruel, frivolous, and irresponsible try to see the good side of these qualities — you are receiving a response that is unconstrained, honest, and playful.
If you are expressing yourself on the internet and find yourself cruel, irresponsible, and frivolous try to experiment with talking as if your words matter, that you could actually create a change in the world or in another person, and that you want to treat that person as you would wish to be treated.