Hashtags

This one scares people, but in reality it is really easy. There is only one main rule, which can be said for most anything on Twitter - don't over use it!

This is simply any topic with a hash (#) in front of it. Why? So that people can (1) spread information and (2) categorize themselves or their conversations, making it easy to search and find other conversations on the same topic. For really hot topics, you can usually find them in the top ten searches trends in the right hand side of your Twitter home. Here is one from June 15th:

One of the most popular ones (to date) is #followfriday. And also anytime there is a social media conference you can be sure there will be a hash tag. In fact, following people who are at a conference is almost as good as being there. People keep you up minute-by-minute of what is going on!

One last thing to note. If you want to creat a hash tag you should first find out if it isn't already being used. Search first, then post - Go to http://hashtags.org/ and search for existing hashtags in use.

If it is already in use you can leverage conversations that are already ongoing around your desired topic. And if you're interesting, they will follow you.

For more information, there is a really great article from Mashable on this.