I'd like to add one more exception to the No Advertising rule.
There are certain people who are more than welcome to post links to their own sites in their posts if this beneficial to the orginal poster. This is at the moderators' discretion of course.
As an example, and I hope not to embarress him, but Wickham (one of our long-standing members with the 2nd highest post count on the forums) helps out a lot here. And sometimes after giving a rather lengty explanation of the solution to a poster's problem, he links to his own site which has more information on the specific problem.
I don't see anything wrong with this and this is the sort of linking that is acceptable. If it helps the poster with their problem then there's nothing wrong with it.