First of all. A forum is like a little community. It sounds cliche, but it really is true.
Each forum community has it's own rules and also it's own definition of what is spam. When I first started posting on these forums I didn't know. I learned though and try my best to fit into each community as I learn what their rules are.
At first I was taken aback at how people reacted to anything that seemed even remotely associated to spam. Some people really jumped all over suspected spammers.
Here is an interesting definition of spam and I think very logical.
If there is a community that is established for a certain internet program, when someone goes into this program without being a member and starts posting about a program that is being talked about in that community, well that is spam to me.
Say you have a community that has to do with personal finance. It is open to the public but is brought together because each and every person in that group belongs to a certain business, program or whatever. One of the products is credit cards lets say. One of the members starts selling a good amount of a certain credit card. A competetor who sells the same credit card finds out about this forum and comres to it to participate, but immediately talks about the virtues of this same credit card.
That is forum spaming and the brand new memer should listen to current forum community about what is allowed.
It isn't right for any new members to say what is right and wrong. That is only common sense.
Tim
ps...Speaking of credit cards, my site
www.usacreditcarddirectory.com has some great deals. See, that isn't spam because it is my blog. ;-)