iPhoto Newbie Question About Library

I have just started to play around with iPhoto. Looks nice, but I do have one question. I imported all of my 2006 photos to date into it, and then created a 2006 library and added them to it. That much worked great, but I expected them to "move" from the main library to this new library. Instead, it appears that the photos always remain in the main library, and that the individual libraries that you create are just different views of them per however you wish to organize them.

Is this the case? If it is, the main library will get VERY big over time, as it holds every photo you have ever imported, rather like the main view in iTunes. Is there any way to sudivide that main library or is it simply supposed to be the huge collection of everthing you have ever imported, from which you may construct any view you wish?

Is there a limit to how many photos you can import into this library before iTunes can't handle it any more? Thanks!

The point of the Main Library is to hold all the photos you have uploaded.
As for photos and iTunes, I have no idea where you are going with that.

Think of it like itunes; Your itunes library contains all your music that you have imported. The playlists below your library simply contain different groupings of the music you have in the library. Now think of iphoto in the same way. You have your iphoto library and all the albums/books below just contain different groupings/views of your main library.

here's my thing. If I have certain folders of pictures, say wallpapers and then random pictures. When I drop those pictures into iphoto should I delete the original from the folders I have since they have now be copied into the iphoto library. I'm assuming the answer is yes, b/c if I didn't I'd have doubles, but then again I'd know exactly where certain types of pictures are b/c they'd still be localized within the original folders I dropped them in before importing them into iphoto. Hope I didn't make it out to be harder than it really is or confuse anyone.

...anyone with some insight or am I just asking a really basic question?