You're measuring file size incorrectly. See:
http://code.google.com/p/closure-compiler/wiki/FAQ#Closure_Compiler_inlined_all_my_strings,_which_made_my_code_size
2013/1/7 Chenesh <
ch...@codeoasis.com>:
> By far, this is a well structured JS compressor, but it still has some
> weaknesses.
> Try typing the following code...
>
> var message = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.
> Praesent sodales, orci id sagittis rhoncus, purus neque ullamcorper neque,
> et scelerisque urna nisl sit amet ipsum. Fusce pharetra aliquet mauris,
> adipiscing pretium augue suscipit ac. Curabitur pretium eleifend enim id
> ultricies. Nam magna mi, ultricies eu dictum vel, semper a augue. Praesent
> eget nunc sem, condimentum venenatis magna. Mauris lobortis vehicula odio,
> nec dapibus nisl eleifend at. Ut eu faucibus ligula.";
>
> alert(message);
> alert(message);
> alert(message);
> alert(message);
> alert(message);
> alert(message);
> alert(message);
>
> and you'll get a -443.58% increase in file size.