what does SPAM mean? (in the internet)?

SPAM stands for "Self Promotional Advertising Message".

Spam is like junk mail, a website or wired service is sending emails with viruses, promotions or information you have never heard of and they keep sending you them emails when you have no idea who they are.

Spam is the abuse of electronic messaging systems (including most broadcast mediums, digital delivery systems) to send unsolicited bulk messages indiscriminately.

Sadly Posting Annoying Mail? S-P-A-M??