No, the networks and games are not connected on the same servers.
you can link the servers of the ps3 to xbox 1 and transfer data.
Microsoft will have a team of people looking after the xbox live servers. I can not say how many hours they actually put into the servers but they will probably be a 24 hour team.
No. Live is a term for the Xbox and the Playstation Network is what PSP and PS3 users have for online games and more. There are no PS3 Live servers only because Playstation has the Playstation Network and Xbox has Live PS3 is owned by Sony, and they have their own servers. XBox is owned by Microsoft.
2.1 Billion Hours
Its not that they wanted them to have it but the orignal xbox live was out of date and costed them to run out of date servers that was not needed and not used as much as the newer servers.
No they do not
The servers seem to struggle on the Xbox 360 and PS3. This may be because they are doing work on the servers, also hundreds of people may be playing at the same time. I can not bet on this but I think the servers will be better on the retailed game.
There are many places where one can purchase used sun servers. There are many used computer equipment sites on the web that offer these servers. One may also use eBay to purchase these servers.
Not anymore, the servers closed on April 15, 2010 for all xbox games
If you mean different varitions of the Xbox... just Xbox, Xbox 360 and Xbox One. If you mean how many there are circulating, it is unknown
Yes, all content on the Marketplace needs either a silver membership or gold membership in order to download content, also remember that one needs a connection to the Microsoft's Xbox Live servers in order to use Xbox Live at all.