How do you know who uses open source?

It’s hard to get a answer. But I am always thanking about this question. The people who use open source may not announce to the wold “we are running apache+tomcat as on-line banking service!!!”. As far as I know, more and more peoples going to choice open source software whenever they have this option.

Let’s narrow down this question. That will be more interesting.

Who are using [**OTRS**](http://www.martinliu.cn/orts/) as help desk on the **Internet**?
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