When ever I want to determine either 1) the prevalance or 2) the popularity of a two different entities, I usually turn to google and check the number of search results... Here are some interesting samples:
Microsoft Memory Leak 264,000 (in hind sight, I probably should have checked Windows Memory Leak - 574,000)
Linux Memory Leak 461,000
Microsoft 188,000,000
Linux 222,000,000
Windows XP 23,200,000
RedHat Fedora 3,220,000
Microsoft XP 17,200,000
Redhat Fedora 3,220,000 (just Fedora - 10,500,000)
McDonalds 2,720,000
Chick-Fil-A 197,000
Burger King 1,640,000
Wendy's 949,000
Intel 60,900,000
AMD 34,800,000
Athlon 15,800,000
Pentium 27,800,000