That's actually part of how I helped grow my account on Twitter. Type a question mark in the search box, and look for relevant questions I could answer. Being useful really helped with engagement, and usually resulted in new followers. Backlinking is good for SEO, which is why I linked back in this post, it helps in search.

I see some bloggers who begin their post with a pic, while sourcing it underneath. That's bad as the source link shows up at the beginning of the description on Google. So instead of the first sentence being about say, fly fishing, it shows a pic link which confuses the search engine as to what your post is about. That's why I list my credits after the post. Replies, bolding, keywords all help. I can see it in Twitter when tweets I made months ago, still get retweets and mentions long after I've forgotten about them.