How responsible are negative positioning on CSS

How responsible are negative positioning on CSS

I'm getting started on CSS and I have the following question:
Is it "responsible" to use a negative positioning on CSS? Can this cause
any conflict on browsers such as IE7,8? What do you recommend?
#example-bottom {
position: relative;
top: -3px;
min-height: 29px;
margin-bottom: 10px;
}