Somebody who actually knows what he's talking about explains:
Vuvuzela is a traditional horn used by South African fans at football matches. It first came to the rest of the World's attention this summer in the Confederations Cup.A weird, and some said irritating, non-stop buzzing noise that distracts you from the football game in hand.
While I also found it quite annoying at the start of the tournament, I got use to it as the tournament went on.
Other, more important, people though aren't as adaptive as me. Whilst FIFA have their concerns that vuvuzela could end up being used as a weapon or advertising board, and want it banned because of this, then players and commentators want it banned because it's hard to communicate on the pitch and the buzzing sound drowns out the commentators voices.
You can understand the concerns as everything that's new looks weird, or in this case, sounds weird, but it's part of the local culture.
It isn't anything different than the chanting in England, the flags in Germany, big written messages in Italian football and so on.
In the end, FIFA made the sensible thing and decided not the ban the vuvuzela from the World Cup, with Sepp Blatter saying: "We should not try to Europeanise an African World Cup".
Whilst some fans still want it banned, having set a up a website to collect votes against it. I'm going to vote "keep it".