Link Building is a controversial topic, especially since inbound links to your web assets are the most important factor in ranking your web pages, and Google's Matt Cutts is now actively accepting reports for improper paid link code.

There are two types of links:

Naturally Acquired Links are generated by virtue of the usefulness of your content, and strength of your brand.  The more useful content you publish, the more likely it is that third parties will link to your web assets. Examples of content that attracts natural linking include:

Manually Created Links are sometimes considered spam—think of message board signatures, reciprocal links, social media profiles (Squidoo, eSnips, Flickr, etc.), social bookmarking sites (del.ici.ous, Blue Dot, Furl, etc.), blog comment links, news comment links, and many others.  This also includes the aforementioned, "paid links," which Google is now actively identifying.

While it is impossible for the search engines to judge the intent of many of these types of links(link spam vs. useful links for your audience), be prepared for the search engines to de-value or ignore these types of links in their algorithms.

Learn more about Ayohwahr Interactive's Link Building services and pricing.