In newsgroups, a message posted that is not appropriate to the topic of the newsgroup, posted in two or more newsgroups, is spam. A message in a newsgroup that offers products or services for sale or even for free, if there is commercial intent, is spam, because this message will be delivered to a large number of recipients. Newsgroup postings that offer services or products are not spam, if they can be documented to be in response to a legitimate inquiry in that same newsgroup, and if they are appropriate to the topic of that newsgroup. A message offering products or services for sale, or even for free, circulated to one person is junk mail. If circulated to ten or more people, or if it results in complaints, it's spam.
Mailing lists are spam, unless the recipients actively choose to be on the list.
Passive registration of list recipients is not adequate. Mailing to your friends, relatives, and legitimate business contacts is not spam. Mailing to lists of people who potentially might be interested in your product, is spam. Mailing to purchased lists, is spam. Mailing to lists of names obtained from newsgroups, is spam.