There was a time when link building meant finding only high PageRank links that used no forms of tracking, but now, free high PR links are extremely difficult to find, and more and more webmasters are using various tracking techniques.
When many people go out looking for links, they tend to focus on higher PageRanks. High PR is certainly useful and very important, but its important to know that those sites have not always had high PR’s. All sites have to start somewhere, and if you can get that free link while the site is at a lower PR why not?
My suggestion, continue to seek out the high PR links, but don’t overlook the sites with a PR 2, 3, or even 0! If you come across a site with a low PR that will offer you a free and relevant link, without taking too much of your time to submit to it, go for it.
We have obtained free links in relevant directories with very low PR’s that now show a PR6 and charge for submissions! This goes for PR0 sites as well… if you find a new site that’s just starting out, and it looks like it has what it takes to move up in popularity, take the link while you can. Always keep in mind, today’s PR2’s are tomorrow’s PR 6’s and 7’s.
Although you should seldom turn down a link, there are times when you should steer the other way. If you come across a site that uses spam or any other ‘illegal’ SEO tactics, stay clear. A link on these sites in many cases may actually damage your placements. Straight link farms are less dangerous, but
will also pose very little, if any, benefit and are best to avoid.
Links on sites that have no relevance what so ever will certainly not harm you, and in some cases may help, but try to keep focus on sites that are related, as you’ll get the most juice from these.