What is the best way you have found to establish back links for your forum?  I have a professional contact E-Mail that I have used with some success, but I am begining to wonder if it is too professional ie coming off as spam or a scam.  Any suggestions?

If you have quality discussions on your forum then you will generate natural backlinks. Many people join multiple forums and will post about something interesting in another forum, with a link of course. Additionally, these links can get picked up by bloggers and other webmasters.

I have noticed that site wide links are not as great as I originally thought they would be.  It seems like Google has kicked one of my projects to the curb on account of it having so many links on just a couple of sites.  I guess I am appearing as a spammer..... or?

There have been some problems in the past with directories also. It seems like people are trolling directories and finding "IDEAL" places to target their spammy junk with.

We have to be on the defense all the time, don't we?

Natural backlinks come only if you have the best and competing content around. Otherwise you'll have to pay for the backlinks. This can be done through directory submissions and blog posting.

You can even post a comment in other's blogs, but be careful enough to post in similar blogs, or else you'll be treated as spam.