Where does ethics come into play with link building?
These marketers never intend to visit the site again, they never plan to participate or become a real member of the community or user-group. The only purpose is to drop their anchor text link within that site because the site has a very good reputation.
That is an unethical practice. You are exploiting the site for your own gain. If, however, the marketer chose to participate and add value to the site it would then become an ethical use of the site and have much more value both to the site owner and to the marketer.
Another unethical practice is blog commenting en mass. Using a software to blast a generic blog comment out to any and every site with a High PR is not only unethical, but also a waste of time. Very few bloggers these days do not monitor their comments. Just for this reason alone.
If you are going to include blog commenting as part of your SEO link building strategy, then have the decency to do it correctly. Be respectful of the blog owner. After all, they have something you want. Add value to their site and they will give it to you.
Good SEO does not happen overnight
Although we live in an instant society, you must come to terms with the fact that not everything can be instantly obtained. Not everything is push button simple. If it were, we would all have instant success. Like any other SEO strategy, link building takes time and effort and consistency.
Natural and ethical link building is the best way to stay in business for the long haul. Yes, you can work to improve it and yes, you can actively seek out means of getting more backlinks, but you must also be prepared to follow the rules and be patient.
There are easy and ethical ways to gain quality backlinks. You want your business to be known as a reputable business, right? If so, do not stoop to disreputable means to gain your success.