Are Group Invites Spam?

[docstarz]

Hi,

Im a newbie here - just joined. My question is, if I have an
email list that I know is highly targeted interest wise to a group I
have created, and if I use bulk mail to send invites to this list -
and if the list is one I have created and is not opt in, and if I am NOT marketing or selling
a product or service but just inviting many people to an online discussion group for the
purpose of reviewing information and discussion - is that legally considered spam, and
how likely is it that if I sent to a list of say around 20,000 people that I would get into
any significant trouble? My current understanding is that this would not be spam since
Im not selling anything? Any input and insights would be appreciated!