As the title says. Here's an image:
This is not my reputation.
As Stefan already stated it is the sum of your reputation of all SE sites. Note that you have a general chat account which is not just for the TeX chat room, but for all SE chat rooms. However, your main site account (which is TeX.SE for you) is registered there as parent account. Because the chat account is for all sites, the total sum of all accounts is shown.