@quid Hi again. If I think a particular user can answer one of my questions, which hasn't been viewed by many unfortunately, is it OK if I ping them under one of their posts to ask them to have a look at my question if they wished?

@stressedout that's not how things are intended to be done. If it happens on rare occasions and in a tactful way, usually no one complains though.

@stressedout I am pretty sure that something like this has been discussed on meta before. I was able to find this question: Is there any way to request an answer from a particular user? Maybe somebody might be able to find other discussions about this topic.

On the more general issue of contacting some user (regardless of the purpose): How to contact a specific user? / Is there any sort of PM (private message) facility available? and other questions linked there. (Basically if you browse a bit through the private-messages tag on meta, you will find several related past discussions.)

BTW if your question is from an area for which there exists a chatroom, you can try also mentioning the question in the corresponding room. (And mentioning your question in the main chatroom is also an option.)

And if the user who you are trying to contact uses chat, maybe pinging them in chat might be a better option than doing so in a comment. (The advantage being that you do not leave a comment unrelated to the specific post.)