First, the good news: It does work by bookmarking sites and of course the page (which is a nice feature as well).

Now for the bad news: Never claim it works in firefox when it loads the site into the sidebar. NO ONE to this day has ever been able to conquer that issue with firefox or other mozilla browsers (or that I know of). The people who should solve that are the mozilla people themselves. Why they have not fixed this issue is beyond the typical website owners who use bookmarking scripts.

This is a module that does indeed bookmark sites (and pages) but it is not fully functional for mozilla browsers. Whoever designs one that does work, they will be famous!