If your thinking about link building for your website. Blog is the most popular tool to build a lot of links from you site.
According to Google, links are very important to them because when a website has a lot of appropriate links to other sites this makes them build good reputation and credibility.
Now taking about reputation, you need to develop your name to appropriate sites. Linking to irrelevant or a spam site would affect your reputation because it would cause problem in your site.
Credibility is one of the most important aspect when you're building your links.
Making some honest comments and articles would really be a great factor in building up your credibility.