Using social proof and testimonials on a blog can positively influence its credibility and trustworthiness in the following ways:

• Provides third-party validation – Others vouching for your content establishes credibility.
• Reinforces expertise – Sharing praise from industry experts affirms your knowledge.
• Builds authority – Who and what organizations endorse you matters for perception.
• Shows engagement – Testimonials demonstrate your content resonates with readers.
• Adds relatability – Visitor sees others similar to themselves finding value.
• Increases discoverability – Social shares boost search rankings and visibility.
• Encourages conversion – Social proof influences visitors to subscribe, buy, etc.
• Lends authenticity – Positivity from real users counters doubts about sincerity.
• Improves brand sentiment – Happy user testimonials cultivate positive associations.

However, testimonials should seem authentic and add value for readers rather than just serve as vanity metrics. The source, specificity and diversity of social proof conveys credibility.