Yes they are going to require new passwords for the accounts and there may be other security procedures
No only one account at a time and the same account can only be active on one PS3. You can have multiple accounts for the PS3 with only one actively signed in and the other accounts not signed in
Yes. All that needs to be done is to have the content on that PS3. When the PS3 looks for the add-on content for any account on that PS3, it will find it because it is stored in a folder accessible to all accounts on that PS3
Over 70 million people have PSN accounts that are not PS3 accounts but allow the PS3 to connect to the Playstation Network (PSN) and use it
The games are downloaded into the harddrive and available for use by all users of the PS3 and are not just for when you are signed into the Playstation Network
Elite shares both your Xbox and PS3 accounts. Your data will not be transferred between them but both are controlled from the same Elite account
If your friend has a ps3 and you both have psn accounts then yes
not at once.
No. It should only slow down if all three are logged in at the same time. Even then it will be unnoticeable.
There is a lifetime limit on the total number of accounts a PS3 can have and after that limit of 50 or 100 is reached you can no longer add a new account. yes you can have as many as you want i have 5 on mine as long as your ps3 has enough memory then yes you can have more than 3 accounts
no
Your credit card details are not held on your PS3 - they are held on the server you connected to, to register your accounts. Think about it... if they were on your PS3, and someone got stole it - they could raid your account before you knew what was happening !
they are the same i think but ps3 is better ;)