Yes I think those two are really good. You can do really well promoting in the WSO, yet I found there is something even more powerful. That is promoting through video. I have been testing video affiliate promotions and they convert a lot better than both article and forum marketing together.
How do you promote your product or affiliate program through video? Could you explain in more details please? Are you talking about video clips posted for example in youtube?
I'll be grateful if you share your experience with us.
It depends on what you are promoting in my opinion. Building up a reputable blog to then recommend products is very successful because you have loyal readers who trust you, and as such you should achieve good conversion rates.
On a blog you must careful that your are not bias towards a company because in that way you lose your credibility. Google words is an efficient way to attract more customers and create affiliate sales.
If you want to promote your product then you have to do the the SMO and SEM of your products to get more traffic to your website.you can use some offpage techniques to promote it in the market like social bookmarking,article writing,content sharing etc.