as for the wifi, is not so easy to set up for thousands of people. i remember at nokia world, with over 2000 people connecting at the same time--my tech friend who was working to set it up said it's not so easy to set up.
you have to have the same ip addressing for people when they move from one side of the room to the other, so the connection seems seamless--you need to make it so people can roam through the access points. it's like with the mobile phone when you are on the train, and you have your phonecall on and you are moving and you go to the area of the other base station with the antenna, you have to continue seamlessly. it's the same with wifi, if i have my browsing connection on and i move from one side of the room to the other side of the conference room i dont want the address to drop. because if the wifi address drops then you have to reconnect, it disrupts the connections. you have to connect again.
you have to have connections seamlessly on all the time and to do that you have to have certain backbone where you have the router giving out the ip addresses from the address pool, and in the pool you have allocated enough ip addresses, and when they move around and go to the other routers, the dhcp gives one address for each client. the allocating of the wifi channels you have to have optimise the channels to get it working as well as possible, because if you have all the access points on the same channel then of course they are using the same frequency so they are eating eachother in the scope. they dont carry as long as they could. there's a LOT more to take into account when producting the wifi connectivity for a conference.
wifi config of your computer, you can select infrastructure or ad-hoc, even in a good wifi
network you can ruin things by putting your computer in ad-hoc mode,
then all people close to you will be connecting to your laptop instead
of the official wifi network. that doesnt really work well. you can
really sabotage the wifi network with the same ssid because people
close to you will connect to your laptop and not the accesspoint. that's
why i kept seeing double of the accesspoints in the venue. oops! it
wasn't really orange's fault
because there are some people that named their computers the same name
as the ssid! they can't control that! so pay attention bloggers when
connecting to wifi at events not to select ad-hoc.
ALWAYS select INFRASTRUCTURE when trying to connect.