An attempt to find what is considered to be illegal internet content can be partly described by the Computer Crime wiki page.
I would summarize illegal content to be any content, images, code, or software that executes or promotes:
Yes, internet gambling is illegal in some states but allowed in others. Recently, betting on internet poker has become illegal throughout all states.
Downloading uTorrent the program is legal in the United States. However, if one downloads pirated content using uTorrent, then it is considered an illegal download.
No adultery is not illegal in Louisiana. Adultery is not illegal in most states but it is considered immoral.
Yes, in most states its considered to be obscene
Yes. It is illegal to make death threats in any form in all states.
All states have a zero tolerance for underage drinking. If the blood content is .02 or higher it is illegal.
Not in the United States, unless you pladiarize copyrighted content.
Disney refuses to release this film in the United States because it is considered racist by today's standards. However, it has been released in Europe. It is not illegal if you have purchased one of those copies. But if you downloaded it off the internet from a non-Disney website, that would be illegal.
If you are inside the United States with an expired visa of any kind, you are considered illegal.
Polygamy is not legally accepted in any state in the United States. It is considered illegal and punishable by law.
In some states it will be considered littering and you can get ticketed.
YES most states its considered a distraction.