Internet discussion forums are indeed a way to drive traffic to your blog and/or website and there are about a billion of them to choose from. Searching for forums, signing up for them, learning their ins & outs, figuring out which ones are worth a damn and keeping track of it all is an enormous amount of work. I KNOW - I've done it.
Essentially, using forums as a method of creating web traffic is an area of specialization. Some people are very good at it. Who are these people? They're the ones who love discussion forums, that's who. I mention this for a reason...
Obviously, you cannot employ every single method of traffic-generation all the time. It isn't humanly possible and there aren't enough hours in the day. You can dabble in all of them, but my advice is to choose a few methods and then concentrate on becoming an expert in those. Ultimately, your choices will be based upon trial & error (that's the big one), your personal preferences, your turn-ons & turn-offs, what you feel good about, what you're skilled at, what you have faith in, what you're educated about, what you have help with and so on.
However, if you are the type who enjoys online discussion threads/forums, then here are a few basic suggestions to keep in mind:
1) Essentially 'social networking', forums are not a place where you want to say something that you'll regret later. Avoid politics & religion. Be neutral in those areas - even if you're not.
2) Though it sounds like an irony, selling is the last thing that you want to do when actually trying to sell within a discussion forum. Remember to 'Tell, not Sell'. You will link to your blog or sales site in your signature (of course) but your comments need to be about your life, your 'story', your take on the topic of the thread and so on. Never, never go in there like a bulldozer trying to sell everybody because it will make you look like a fool.
3) Understand and know that forums are a long-term project. Be aware of that going in. You have to build respect and trust in these online communities. That's what it's all about. The good news is that most people (as in just about everyone) won't put in the effort. If you're willing to take the time, to learn and to apply yourself, then you can be influential - even a dominant force.
4) You want to change up the wording of your signature on a semi-regular basis and/or add a P.S. to your messages. The P.S. tends to psychologically create the sense of urgency. Plus, many readers scan to the bottom of posts and read the P.S. first! Changing your signature is simply a way of getting new attention for your link from those who have seen the old signature for too long.
5) Though this is one of the fundamentals, your link should lead to an opt-in form to get the reader onto your mail list - i.e. out of the forum and onto your auto-responder. To to this, you will need the offer of a free gift, a free report, an e-book or some other defined benefit - something genuinely useful. As an example, I have an opt-in subscription form in the upper right-hand corner of this page. If you haven't subscribed to my '30 Day Success System', go ahead and do it. You'll receive a lot of good information and it just might inspire you!
6) In any kind of social networking, never try to 'dominate the page' with a dozen posts in a row (a common annoyance) or be a 24/7 lurker. You'll never get anywhere with either strategy. In fact, it's destructive. However, one thing that you can do is occasionally respond to your own posts and thereby get yours back at the top of the thread. You do this by adding some additional information, a chart or table, an update or something that you 'forgot'. Please be subtle when doing this or you will defeat the purpose.
7) Last but not least, if you have a great forum post, put it on multiple forums and your blog as well. Make it an autoresponder letter too if it's appropriate. A good piece of writing should be put in as many places as possible. If you stay with this business over time, that piece could be part of a future e-book or even a real book that you could sell in stores. Never let good writing go to waste!
