I would use general topic like shopping, food, the weather, plants around you and avoid topics that generally people argue about like religion, politics and things like that. You also need to work consistently at things here to maintain interest from the other party. All good advice that I don't follow :-)

There's a saying in the U.S. that the three topics that lead to arguments are "sex, politics, and religion." Avoid these topics at first, however curious or interested you may be. Even when you think you are getting to know someone, be very careful about these topics. This is especially true when you are talking to somebody in a different country.

I guess some topics like how much they earn can be considered unpolite to talk about, but in general just try to be ready to drop a topic or question if they say they are not open to talk about it or that it's personal, without making a big deal about it, and you should be fine. In general, if you try to be a good person, that's enough. People come and go, so always look for new ones to replace who's busy or leaves.

you should answer them and don't leave them and go to facebook :D

thank you all really