There are many posts that are just paraphrased news articles which get tons of upvotes. I avoid up-voting such posts except when I see a huge reward potential (yes, I know ... greed). I don't like when people post somebody else's video from Youtube and hope for upvotes. There are really a lot of spammers on Steemit.

You must be very careful when flagging people's posts because this could backfire on you. It almost happened to me when I saw how a user copied other user's work and when he noticed that I flagged him he immediately flagged my latest post. He had more reputation and Steem power which damaged my rewards.