Once upon a time, it was damn hard to generate a good favicon. One that worked on all majors platforms. Not just Windows, but also iOS, Android... Sure, there were a lot of favicon generators around, but they only gave you a favicon.ico and leave there.
RealFviconGenerator came to relieve the pain. It generates all the pictures you need. Not just the favicon.ico, but also the dozen of pictures you need to get a good result on all major browsers. And also the HTML code, which is not the one-line-oh-so-easy most sites advertise.
More? RealFaviconGenerator also checks your existing favicon and let you know what's good and what can be improved.