The club have around 100,000 members. Every four years those members vote for a chairman and a board who then run the club for the following four years. Those members have a distinct voice and say in how the club is run.
It's perhaps also worth noting that the club also run teams in other sports. Winterthur FCB (From 2007/8 AXA-Winterthur FCB), FC Barcelona, FC Barcelona Futsal and FC Barcelona Sorli Discau that compete at basketball, handball, futsal and rink hockey respectively.
There are also a number of prominent amateur sports teams that compete at rugby union, women's basketball, women's football and wheelchair basketball. These include FCB Rugby, UB-Barça and FC Barcelona-Institut Guttman. Other amateur teams represent the club at ice hockey, athletics, baseball, cycling, field hockey, figure skating, and volleyball.
Back in the day Sir John Hall tried to build something similar at Newcastle with rugby teams, basketball, ice hockey etc. all under the Newcastle brand but it never took off there so it's testament to Barca I think that they have made such a success of them all.
Jimmy Burns has written a decent overview of the history of the club
http://www.amazon.co.uk/Barca-Peopl...6649233?ie=UTF8&s=books&qid=1182164898&sr=8-1 only a couple of quid if anyone fancied an interesting read.
On comparisons with the leading clubs in this country I think only Man Utd are of the same scale and they too are a club who's management over the past 20 years I have much admired. Arsenal have established a style and identity under Wenger that will no doubt make Gooners proud of the club. The other two are nothing imo.