Absolutely... Positive, helpful cross-posting is fine and can be very beneficial.

Cross-posting the same announcement to a dozen forums to solicit people to one's own website or to buy a certain product (which would also be 'spam'), is the kind of thing we're looking to stop.

Sometimes I'll see a newer member who's not sure where to make their first post, and so does so in 2 forums at the same time. That's okay too. If they did the same thing to a dozen forums, it would probably be less okay (but we'd just let them know privately and delete some of the duplicate posts where it was clear they didn't belong).

John