Blog comments are still highly useful both for SEO and building your brand. It engages others in the conversation while it's happening, showing you're a leading expert in the niche.
If you provide a link, make sure it's contextually relevant and adds value to the conversation.
CAUTION - link text should be generic:
-your company name
-your website name
Google will penalize you if you link too much using a keyword in the link text. Save "keyword links" for a select few high-quality articles on solid sites.
Author - 102 Free and Inexpensive Ways to Leverage the Internet
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