Let us say that someone is hosting a web application where others can come and register and use for free(like stackoverflow or stackexchange). Is a terms of service agreement necessary? Like this TOS for stackexchange ? If there is no TOS agreement, are there any implied(default) legal conditions?
If there is no TOS agreement, are there any implied(default) legal conditions?
Ask a lawyer. Seriously, nobody here is qualified to give you legal advice. (And if anybody was qualified, they'd also know that they shouldn't!)
The real point of the ToS is to make it clear what the ground rules are, what the site owner's obligations are and to reduce the arguments (and threats of stupid lawsuits) if they need to boot someone off, withdraw service, or whatever.
This really depends very much on the country you're in.
- In some countries ToS is just CYA for the owners.
- In some countries you're required to have ToS, and it's considered contract between owner and client (thus owner can be held legally responsible for not following his own ToS).
- In countries with codified law, the law always has precedence over ToS, thus any parts of ToS that contradict it are invalid. This creates kind of weird situation, when service is located in one country, but clients are connecting from another.
A ToS is designed to protect the page owner. If you have any reason to believe that others using your page might try to take advantage of you in any way, then you should have a ToS to address those concerns. In actuality, there is nothing requiring that you have one and default legal conditions are what you can convince a jury or judge of should the need arise. I am not a lawyer though, so take this with a grain of salt.
On a more mundane note it protects you if you ban someone for being a jerk. Honestly I think internet jerks are a lot more common then wana-be-bombers.
you'd probably be legally responsible for any and all illegal activities performed through your service by its members.
So if it were used by some terrorists to communicate about the next Oklahoma City bombing, you could possibly be arrested and convicted for it.