http://boost.org/more/lib_guide.htm#License

License requirements
Must be simple to read and understand.
Must grant permission without fee to copy, use and modify the software for any use (commercial and non-commercial).
Must require that the license appear on all copies of the software source code.
Must not require that the license appear with executables or other binary uses of the library.
Must not require that the source code be available for execution or other binary uses of the library.
May restrict the use of the name and description of the library to the standard version found on the Boost web site.