I was thinking of the same issue just yesterday. So far, I post photos and content which are my very own. But if there are some information which I find useful and want to share with my steemit friends, I will always give credit to the author or origin so that everyone is clear where it is taken from....I also find the "resteem" function of Steemit very good. Gives me a chance to share useful information or things which I find interesting....