html script tag not using type javascript <script type="text/html">?
Script elements that have an unknown content-type are simply ignored, in this case, the browser doesn't know how to execute a text/html script.
It's a common technique used by some JavaScript templating engines.
See also:
It's a trick that I first saw in a John Resig blog post. It's used for stuff like holding a template to be expanded later. The browser won't make any attempt to execute it.
The "benefits"? Well, it's a lot neater than keeping a string in your Javascript code directly. Because you don't have multi-line strings in Javascript, it's messy to define a template like that.
edit — ha ha yes, CMS has linked the very blog post in his answer!