Online etiquette

Be considerate in online discussions: if you participate in discussions, be polite and do not disturb or offend others. Make sure that your message stays on topic. Disturbing or offensive users may be tracked down later, even if the discussion has been anonymous. In case of a problem, contact the site administration.
Take care of information security: Keep your passwords in a safe place where others cannot access them. Never divulge your passwords to other people! Make sure you do not send or reply to virus mail. If the message title or the name of an attachment looks suspicious, delete the message without opening it.
Know what you are agreeing to: there are services on the web that you have to register for. Read the sign-up instructions carefully and make sure you understand them before agreeing to anything. Do not say yes, unless you understand the question.
If a service requires registration and asks for your personal information, think carefully what information you want to disclose about yourself. Be especially careful in giving out your e-mail address to avoid becoming flooded by spam (junk mail). Also, be extra careful when sending credit card details online!
Be critical: bear in mind that there is no publishing threshold on the Internet, so anybody can publish almost anything. Not all information found on websites is true or accurate. If an offer or service sounds too good to be true, it probably is. Particularly dubious are e-mail messages that advertise significant financial benefits or medicines that may be illegal in Finland or dangerous to the user.
The web has a long memory: do not forget that everything you write in an online discussion, e-mail message or on your own page can be read many years from now.
The law and the web: Everything that is illegal is illegal on the Internet as well.
LAWS AND REGULATIONS
The Internet allows for unprecedented freedom of communication, but the freedom comes hand in hand with responsibility. For example, the author of a website is always responsible for the contents and legality of the site.