I haven't had a chance to read all the responses, so forgive me if this has already been stated, but I use the word "dismiss" rather than "ignore". I find there is a subtle difference. For me ignoring implies turning a blind eye...not making a choice to either accept or deny, but to just be unaware, to just blindly push away. On the other hand, Dismissal means I see, hear, recognize the situation for what it is, then make a conscious choice to dismiss the information as false, inaccurate, or otherwise wrong for me. Don't know if that is a difference for others, but it is for me.
Also, being able to truly ignore something, I think comes with a true indifference. Otherwise it is like I see my second graders doing...they look straight at their peer and say, "I'm ignoring you"..."I'm still ignoring you"..."can't you see that I'm ignoring you?!" LOL