Blog commenting is the practice of leaving comments on blog posts in order to engage with the author and other readers, share thoughts and opinions, and build relationships within a blogging community. Blog commenting is a way to provide feedback to the author and show appreciation for their content. 

Profile linking is a technique in SEO that involves creating profiles on various websites and linking back to your website from those profiles. This technique is used to build backlinks and increase the visibility and credibility of your website.