Reason for that assumption: Not many posters show worry whether their posts benefit the forum they post on.
Other than direct traffic I have never once seen a benefit from posting on forums when it comes to ranking higher in Google. Maybe back in 2004, but that was niche specific forums. General forums and non content related websites in your link don't seem to make any difference. I am not sure what sort of results people get who pay someone to post on 100s of forums with the same link for them, but IMO the money you spend on something like that would be much better spent elsewhere.
Yes, forums is the best traffics source for your site. But you must be active as contributor if you want to get huge of traffics from them.
Traffic is not consider spam still now so that why its beneficial now a day.
yes.. Forum posting works well now also.. Do it perfectly and too naturally.
Yeah It is still beneficial and people use it as an effective tool of SEO. Not only for SEO purpose but such forums enriches your knowledge and you can make a network here and exchange the ideas that help you grow your business.
Yes, Forum Posting is a good way to share your thoughts and opinion. It also helps you to increase your link popularity. Its a great link building method. You can promote your website through use of Signature on forum profile, your Signature links detected by Search Engines. But Make quality posts on forums and not post just to get your signature link shown.