Understanding which link opportunities will provide actual SEO value is key to a good link building campaign. If all your efforts go into building links that don’t contribute to your rankings then you are better off not wasting your time and money.

So how can you tell which links are good in terms of SEO value?

I recently read a good post that began to examine this issue covering the important basics – but I thought that the topic deserved a bit more explanation so here it goes:

What to look for:

• Is the site an authority? Make sure that the site itself ranks for what it’s optimized for. Search its Keyword targets and make sure it ranks in the top 50 for its own goals.

• Does the site help other sites it links to in terms of organic rankings? Look for other outbound links on the site/page and search the anchor text of those links to see if the link to site is ranking. Look up its other links to try to determine if the linking site is partly responsible.

• Make sure that the site does not devalue links using no follow attributes (In link tag, robot.txt, and meta).

• Make sure that links are coded SEF (search engine friendly) straight HTML is the best – frames, redirects, and scripts are problematic. Although scripts and framed links can still pass authority, I’ll always go out of my way to ensure that the links I build are HTML to avoid potential crawling issues.

• Ensure that the site itself is not penalized or sandboxed.

• Make sure that the linking page is not saturated with other links (many SEO pros look at only external links, I like to consider internal links as well).

• Site Age is important. The older the better! New site typically don’t pass authority as they have not earned trust with SEs. This is not always the case but is usually.

• Make sure that the linking page is indexed.

• Make sure that the page is unique and not duplicated, on other sites or within the linking site.

• Checking cache date is good, but can be misleading. If a site was cached yesterday coincidentally you may assume it’s crawled regularly, without understanding that it may not have been cached for 40 days before.

• Site or page PR can be used in two ways.

(A) If the root is a PR 0 or “Not Ranked” then you might want to avoid it (but not always)

(B) by checking inner pages for PR where no, or few external links into the pages exist then you can assume that the site passes authority.

• Is the linking page permanent? Blog links are common, but getting a link in a post that may be moved or archived as new content is created makes for a little investigation work. Look at how older posts get archived and make sure that inner page PR is on older posts and posts are indexed as well. Extra Tip: support blog post links by building other external links into those posts to the actual permalink.

• RELAVANCY? I think relevancy is important for a variety of reasons, but I also know that relevancy can be defined loosely, and I am familiar with many sites that don’t optimize for relevancy but still hold competitive organic search rankings, so I want to be careful about using relevancy as a factor in assessing “SEO value” in terms of this discussion. However, sticking to relevancy is good practice. Relevancy in a linking sites link portfolio in addition to its on-page is important. I view one link from a site to be a piece of the linking site’s entire link equity. Therefore, I also like to make sure that relevancy exists in a sites link portfolio and not just its content.

• Link Neighbors – make sure that the linking page is not linking to other sites that you would not want to be affiliated with. This means checking the link portfolio of other linked to sites on the linking page. It’s a bit of work but will add value to your efforts. Watch out for link neighbors that spam or have been penalized by the search engines.

• Link to Content ratio: Building links into content is the best. In any case try not to be grouped with a list of links in footer or sidebar or on a page in general that resembles more of a site map where there is more links than content.

Considering all of the above points will help you better assess the actual SEO value of the links you build. I hope it helps to shed more light on the topic. If I’ve missed anything please contribute to the list!