I haven’t recently, but when I am trying to solve a problem and come across a post/comment which does a great job of helping me out, I’ll sometimes post a “thank you” to the author. On the receiving end of things, I had posted a couple of kinda useful scripts in the PowerShell sub-reddit and would get both “thank yous” and questions regarding those scripts from time to time. I also had a really popular post (it’s still linked in the wiki) in the cordcutters sub-reddit which elicited questions years later.