Paul gives us a new filter through which we should evaluate our actions: avoid participating in activities that are stumbling blocks to others, whether they draw you from Christ or not.  Ultimately, this isn't any different than Jesus' reminder of the commandment to love our neighbors as ourselves.  When we love other people, we avoid actions that cause other people harm.  One specific example that I can think of relates to alcohol when I was a teenager.  For whatever reason, my parents have opted not to drink.  It's not a value judgment on those who do drink; they just choose not to.  When I was in high school one of the main things that kept me from drinking was the fact that my parents didn't drink, and if my parents hadn't taken that approach, then there's no doubt in my mind that I would have made some different decisions.  It's not a sin to drink alcohol when you're of legal drinking age, but my parents were able to keep from being a stumbling block to me through their abstinence of alcohol.  It's important to consider how our actions might affect and influence others, and we should seek to avoid doing things that could potentially cause others to sin.