satine
I believe that if your heart is in the right place, it's fine to do readings about other people-- how they are doing, what they might be dealing with right now, and so forth. If you are using the tarot for your own or another person's spiritual development and growth, then you have to recognize that we are all connected in different ways. No man or woman is an island. That said, even if you are reading for just yourself or another person who is sitting right there asking you to do a reading, you are going into questionable territory when you start using the tarot for superficial fortune-telling. This is the line you wouldn't want to cross in my opinion. If it feels like you are using the cards for a solely earthly purpose, then you should probably step back and take an honest look at your (or the other person's) motives, what you want to accomplish by the reading, etc.