I am curious about merging a .sql dump from closed sites with our site to increase our traffic, member and post base. Should everybody from the other site be given the choice to have their info given (or sold?) to me?

I woudn't think so. If a restaurant is sold, the owner doesn't ask all the customers either.

What I would do for sure is post an announcement a while before the merger.

It really depends on the types of forums. I mean if I was posting on a certain forum for reasons like it's small or something, and then it merged with this, I would probably just forget about the account in the first place. Perhaps that forums owner could just give the option to present this forum and say 'Hey, if you're interested in all your postcount/information being moved there, let me know. the only thing though is importing posts/threads from there would seem out of place, what if they don't fit into any of these categories?

Is it legal to signup for a newsletter and your email being sold to another company for a profit to spam you? Yes it is! The wonders of the legal system. So I guess I think its ok as many of us already get it done to us anyways.

Is it legal to signup for a newsletter and your email being sold to another company for a profit to spam you? Yes it is! The wonders of the legal system. So I guess I think its ok as many of us already get it done to us anyways.
I may have misunderstood the laws that govern, but I have been lead to believe that it is not legal. Furthermore if we gather e-mail addresses as part of a registration system and don't notify people that they will receive e-mails that this constitutes SPAM. (I should note that I live in Australia and our internet laws may differ from those of other countries).

On a personal note, I would like to be notified if my details of Forum X had been transferred to Forum Y. I like to keep up with all of the forums I am a member of and if my details are transferred to a new forum I would like to know so that I can log-on to read about what is going on.

As an admin contribution is more important than total member stats. i.e. I would rather have 1,000 members all of whom were prolific posters than have 10,000 members of whom only about 20 bothered to write anything.

In my opinion, i would tell the persons from your closed site about the merge, and get their opinion. Then proceed from there ..

If I remember correctly we informed the members on creations.nl and requested everybody to contact us prior to the merge. This way if someone doesn't agree to get their details moved over to the new server and community they could request to get their accounts purged/pruned (whatever the word is).