Power Bars that accommodate adapters

I am looking for any informtion on power bars. I have seen them with a swivel at the wall-plug, with separate 'adapter' plug holes, etc.
I want to know if it is necessary to plug and an adapter into it's own spot and why...

 

The reason most of those do that, is because adapters are huge and bulky, and its makes it hard to fit multiple adapters in a small strip with out the swivle/spaced out plug ins.

 

Thank you for your prompt reply. The swivel plug is at the wall socket. The plug-ins on the power bar are not the 'swivel' type; they are stationery. Is it true that the wiring is the same to the three-prong sockets as well as the two-prong? When a power bar specifies 3-wire what are they referring to?

 

The third bar is a ground, usually people get by with out it, but if its asked for, its best to do it that way.

 

Thank you. I am looking for as much information as I can as my son has his first computer and he bought Christmas tree lights power bar.....made me wish I could stuff him back in...I decided to buy him one myself and gather as much knowledge as possible. He is 'old school' still...'woman do not know much'. He will believe one of the 'guys' before he will believe 'mom'.... unless I can knock him down first (all 6'2" of him) and then knock him out....and then run like the wind. I would not be surprised to see him on MajorGeeks before too long. I am browsing the site to see what is going on with everyone. I think I am going to like it here. Thank you again.