Gordy, this is something that can be very important..
Don't just make lots of posts on forums with your name in your sig, this won't bring new clients.

If you are making posts that are helpful, going into detail, creating posts that are interesting and involving then people will notice this, they will take more notice of you and in turn, your company.

Would you take more notice of a company and think it is professional if the owner made 1000 posts that were just replies for the sake of upping their post count and getting their sig on the site, or would you take more notice of someone that did 300 posts, each helpful to the poster if they are replying, or something with a little effort put into the post that interested the post.

Your posts will reflect on your company if you have it in your sig, if you make a post that gets people angry, they will relate this post to your company on the other hand, if you make a post that is helpful and you go into detail for the user, they will think of your company as one that really pays attention to their customers.

Some people don't even include their company name on forums they post or tell people who they are simply because of this reason.

You have to keep a good profile where ever you are posting if you are advertising your company at all.