I was reading through some old threads on the Pensieve, but had some questions of my own to add.
It seems the general consensus is that when you take out a memory to view in the Pensieve, you still remember it yourself. . . except for that bit with Snape in OotP. He took out memories and put them in the Pensieve, presumably so Harry would not see them if he somehow managed to break into Snape's mind. At least, that's how I interpret it. Do you think he put them in there for another reason?
So if you take out a memory and lose it, you have to put it back to remember it. Do you think you can copy it so someone else can study it? It seems like Slughorn must have done something like that. He gave Dumbledore a fake memory, but then pulled out the real one for Harry later on.
I saw some comments and have to agree that Dumbledore's Pensieve probably isn't the only one, but that they are rare. I find it very possible there are some floating around, or being used at the MoM. So here are my last two questions: what do you think happened to Dumbledore's Penseive after the Battle of Hogwarts? Did it stay with the school?
And do you think it could be in any way possible to create a temporary Pensieve using a magical spell? Like, a very powerful, relatively unknown (or even new) spell that might turn a bowl of water into a Pensieve? I tend to think almost anything is possible with magic, so how could that work in a story?