If by "memory" you actually meant "RAM", the main difference between RAM and the hard-drive is the access time and the amount of data accessed at one time:
Note: there are other differences relating to physical construction, power consumption, volatility, etc.
What is the difference between a regular memory card and an Ultra Memory card
what is the difference between the memory store model and the working memory model?
PS3 has a Harddrive which you can change with a standard laptop harddrive
No, but it does have 512MB of internal flash memory.
PS3 has a harddrive not memory cards
yes more memory
Marketing.
Either buy a new harddrive or buy a memory card.
That would be virtual memory. Its when your the excess data is stored on your harddrive. A section of your harddrive is reserved for this purpose. Though virtual memory isn't as fast as normal RAM.
No the PS3 has a harddrive to save
No. The kinect has no memory storage.
Memory is microchip; address are processor board slots