Hi @eaglespirit, that kind of upvoting is allowed, almost expected, otherwise they wouldn't have put that option there. 😉 the only bad thing with that, is it automatically depletes your voting power, which you may not notice or realize as it's happening.
I think what is being referred to most often, is the practice some people have (and I don't quite understand how it could work) of creating multiple steemit accounts, and having those accounts upvote your ¿main? account? then others see you being upvoted a lot, and not knowing any better, like good sheeple and come along for the ride and start upvoting as well.
You can invest your own Steem and pay to have your article put in the "Trending" category too, which will bring more votes, even though your post is crap.
That is how I understand, albeit imperfectly, what all the hoopla is about.