The exact number of Linux users has always been an illusive answer. Everybody wants to know, several have tried, but no one really knows how many people use Linux. But openSUSE knows how many people downloaded their 12.2 images in the first 24 hours after release.
openSUSE usually sits around the fifth position in Distrowatch's Page Hit Ranking list getting around 1500 hits per day and it is occasionally included in Top Five lists. Last popularity poll I ran it came in tied for second.
rest here 
Also: Greece hosts 2013's openSUSE Conference