> If you want more people to reply to your future posts, take the time to reply to them. 

That's a good point. And I'm sure you mean replying with a good comment, adding more value to the discussion, not just replying with a short, stupid bot-like comment, right?  

Taft

Should I reply or not to every comment on my posts?

If you want more people to reply to your future posts, take the time to reply to them. It's a bit of an art to figure out what's worth turning into a conversation, but it's a valuable art that applies beyond SN.