It's so easy to find the latest trending topics in the world or your specific geographic location on twitter.  Just login into your twitter account and look at the bottom right of your twitter page where it displays “Trending: Worldwide”.  Obviously it will say “Trending: Worldwide” if you want to reach the world with your message.  If you are wanting to reach a specific geographic location, for instance Dallas, TX then you will want to edit your Trending Topic to list Dallas-Forth Worth to meet your specific cities geographic location.  Below “Trending: Worldwide” you will see different keywords listed.  If you want to be a part of the hottest topics on twitter, all you have to do is type one of the keywords into your twitter message and send it out.  Make sure the keyword is relevant to the twitter message you are sending out or else you will upset your followers.  Go try it out and see how easy it is to interact and communicate on twitter.