If you consider yourself an SEO, then you must know that links = ranking on the search engines. When I first started out, virtually any old crappy link would do. Even FFA links worked okay and got your website ranking well.
However, times have changed, and since 2003 and it has become much harder to rank your site well, especially on Google. This is because Google has changed its search algorithm and is filtering the majority of links.
Google filters out and doesn’t trust the vast majority of links on the Internet, and I estimate this to be as high has 99% of all links. If you’ve been in SEO a while, I’m sure you have tried to broker some bargain deal where a guy in India will do “1000 directory submissions for $50”, only to discover it was the worst $50 you’ve ever spent.
If you want your site to rank, forget about “wholesale” links. These include links from directories, article sites, forums and similar places where you can go and get “a lot of links” without any editorial judgment easily. Even paid links fall into this category, with a high percentage of paid links being filtered out. Even what are deemed as “bulk” links where you can make 3-way link exchanges don’t work very well.
“Mechanical SEO” is almost dead. Where you can churn out a website, get some links and rank well. It’s so much harder to obtain decent rankings on Google, the algo is very SPAM resistant.
However, it is still possible to obtain good links, and the easiest and most cost effective way is through link bait. Linkbaiting can be a hundred times easier than going out and manually tryng to find non-filtered links. A good piece of link bait can generate tens of thousands of links, and can be created in a couple of days.