Some people I seen say Twitter is very profitable. But I tried it myself and I haven't generate a single dime myself on there. Facebook and Youtube is pretty much where I would get my traffic from mostly. The most common way I seen some marketers make money off Twitter is building a local business Twitter following for them.
I was talking about the business of twitter itself not really how profitable it is for the users.
When you are talking out of the users perspective, you are probably right.
Youtube is a good way to get your website ranking organic in the search engines. Make video's and put a link to your website in the description.
Twitter is more to engage with your audience and give updates, not really meant as a backlink strategy for seo purposes.