We bang on about showing interest in others, and rightly so! You can't expect your own content to be popular if you don't make the effort yourself.
However, we understand that you're often very busy. Risking a comment 'just for the sake of it' may result in your comment not seeming genuine.
Using the 'like' button still shows your fellow members support, and shows up on the activity feed on the homepage, so you have your own extra slice of visibility!
I reccomend using the like button occasionally but still focusing on interacting genuinely with others by commenting and messaging - as it will get your further. This is just a handy helper for those days when you can't dedicate much time.
Did you know about the like button?