I typically use my social media to promote my Webtoon link, since most webcomic readers already have accounts there. But looking at the poll results, I imagine the experience below holds true for Tapas as well.
I've had Blue Star Rebellion retweeted on Twitter by the Canvas team twice. What this indicated to me, more than anything else, is that they know it exists. It's no guarantee of later promotion, but getting the right eyes on your work is a good first step.
In my case, I did end up in one of the staff picked sections on Webtoon a few weeks after the second retweet. I attribute that to their finding my comic on Twitter.
With Tapas, I don't often tag Tapastry on my social media posts. (You can only squish in so many @'s and #'s before the algorithm thinks you're spamming!) But I'm quite active here, which probably makes me more visible than social media tags would. I've had front page promotion twice on Tapas, one which I think was algorithmic, and one currently active, which I know was a staff pick. 
