If you are looking for forums as a traffic driving channel and actually looking to create buzz for your brand then yes forums is one of the good sources. But the problem with most of Newbie participating in forum is how to do that. Often it happens that the moderator either warns or bans various new entrants in forum. The reason being “using forum as a platform to Advertise.
NO..forum is not meant to advertise or market your product. It is place where people come, discuss and try to find out solutions to their problems. Forums moderators or admin are very strict with the rules of forums and perhaps we all must comply with the rules as doing anything against any rule is definitely “Unethical” .
Here are a few tips that you should Not do while participating in forum:

Marketing: The first thing you should drop from your strategy list to market your products on forums is Marketing. Forum is not the place to market your product the way you use print, television, or paid online advertising, or for that purpose any other medium or platform.
Trying to cheat the system: Most of us try to cheat the system when it comes to promoting brands on forum. We feel by creating different IDs and by asking indirect questions we will manage to cheat the system and will easily get our brand pushed through forum. You may gain success for one or two days but I am 100% sure the forum moderator will catch you. Their job is to save the basic sanctity of forum and they take their job pretty seriously.
Irregular or rare Participation How often you visit a particular forum and your contribution is counted. The number of posts you have under your sleeves and the valued added answers being provided by you. All that matters! So do not be irregular in participation.
Creating thread to promote your brand Do not ask questions like have you heard of XYZ brand? or have you ever traded with the company ABC? Or anything similar to the given examples. This is completely unethical and the moment moderators sees it your account will be banned.
Participating in same forums with different IDs: Never participate in same forum with different IDs as the IP is also tracked plus more importantly the set of questions asked by you and your colleague using different IDs will all be somehow related and that becomes a reason why the forum owner will frown and make it sure by warning you or even banning you that you refrain from such practices.
What Should you do while participating in forums 
Be transparent: Create your account with your original name. Use this platform to bring new values to the members. Be recognized. If people value your answers they will try to find you out on other social networking channels as well. Your credibility on forum can further be increased if your identity across the channels remains same.
Find Niche Forums: Participate in forums that are directly related to your business or your expertise. This will help you add value to the forum threads. And remember only such forum will have the target audience you want to reach out to. This will help in translating your efforts into results in some time.
Add Value: Forum owner would love it if you go ahead and answer open threads. You must answer only when you have something to add do not do it just to increase your post count.
Regular Participation: Make it a habit of participating regularly in at least one or two forums. You can only make your presence felt if you participate in multiple discussions and leave behind some value to the open threads. You can also ask questions as that makes your presence felt immediately as most of the people are interested to know the person who has asked questions.
Use Signature: Once you have credibility and good number of post you can use signature. The signature can be used wisely to make your brand visible to everyone. Plus once you have significant presence on the forum, you can subtly convey your brand message.
Remember, the forum exists because it offers value to its member and its success only depends on the number of participants coming in. So plan and strategize your participation in forums and I assure your brand will definitely go viral.
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Forum posting is one of the best ways to gain quality one way links. One way links are when a website links back to without you linking to them. These links are a very important factor that search engines use determine your website’s rankings to your website. Also this is time consuming yet effective seo approach.
Hi! I like your article and I would like very much to read some more information on this issue. Will you post some more?
Could you recommend any specific resources, books, or other blogs on this topic?