I stumbled over the above web service some days ago, because a friend was asking for help in getting a certain configuration file to work. There was a closing bracket missing somewhere, was what the application told him, but he couldn't spot the error.
Although I didn't know that application, I offered my help. You know, sometimes you just need a second pair of eyes looking at something and explain the problem and you even come up with the solution yourself.
That said, instead of sending me an email or whatever with those config lines, he used the above service, which I found to be pretty cool. It does syntax highlighting and adds line numbers to your source snippets. Others can modify the snippet (like, if they found the error and fixed it).
As the source code to that page is available as open source, you could even set it up on your own server and tailor it to your likings.
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