Diagnostic and usage has low memory logs

Question

I noticed that I have 3 memory low logs in my usage data which makes no sense to me. I am careful to close out my apps and shut off my iPad when not using.  I
How much memory do these come with? I have 64 gb so have plenty of storage but that is not the same as memory unless macs are different than pcs in that regards.  I pasted part of one below and do not understand how I could have 25722 pages active. There is no way I have opened that many pages. Can someone explain this log to me?
thanks
Incident Identifier: A9C3CFBE-FB45-41FD-8FA0-8FF5F015FB34
CrashReporter Key:   12003f29baf1f3529d1bdf5b6e1c0d370e87cfc3
Hardware Model:      iPad3,1
OS Version:          iPhone OS 5.1 (9B176)
Kernel Version:      Darwin Kernel Version 11.0.0: Wed Feb  1 23:18:07 PST 2012; root:xnu-1878.11.8~1/RELEASE_ARM_S5L8945X
Date:                2012-03-23 20:26:40 -0400
Time since snapshot: 70 ms
Free pages:        1489
Active pages:      25722
Inactive pages:    15514
Throttled pages:   146872
Purgeable pages:   20388
Wired pages:       57253
Largest process:   Facebook
Processes
         Name                 UUID                    Count resident pages
              CW <02d0b979949f35cb805fb49a4092eb98>   11585
  SolitairesFree <e92412f375a9327b89d44596f1ee2e55>    1950
Game Center~ipad <4def5485a9b63af5bd44081374f911b0>    7217
        TWC-iPad <eccce978a7fa31499bcd7b98d3d1cebf>    8254
     Preferences <f7fe5488030c3dc7bd7a7eb0b43d3f88>    2288
        AppStore <6048ba6872873eacaf9891d916676324>    9654
      MobileMail <eed7992f4c1d3050a7fb5d04f1534030>    1645
     MobileStore <f93e54a78c833aedaae9ccdc2d454ddc>   13803 (jettisoned)
        Facebook <634c3f44446b37e38e896aacfe5db282>   48165 (active)
      Music~ipad <feaeeb513e9c35c99e16dcc59d2fee82>    1429
WordsWithFriends <f5f78622781e336982b296542844b81f>   23831
        networkd <10e39e61090b3c999ae580c8a2b862d0>     267
      aosnotifyd <9fbc1c99b00f34c5978eabca0ed855d6>     713
        BTServer <f3607d9648b93be69fbec2e2e7bb7c97>     345
      aggregated <a12fa71e6997362c83e0c23d8b4eb5b7>     508
            apsd <0f4cea84e4833057ab2816ca5d9e4b7b>     452
     dataaccessd <473ff40f3bfd3f71b5e3b4335b2011ee>    1177
    fairplayd.J1 <e21189305e6b339b8bb329d3f06ecf31>     372
       fseventsd <914b28fa8f8a362fabcc47294380c81c>     256
            iapd <84e86122efe33ef7a9d874a8d86f07ef>     693
         imagent <a17aacef550b334496f644607a6bb12c>     498
       locationd <de6edddaae23368db41a2d1d3ced1503>     940
   mDNSResponder <86ccd4633a6c3c7caf44f51ce4aca96d>     353
    mediaremoted <327f00bfc10b3820b4a74b9666b0c758>     394
    mediaserverd <2fb463599bb63562a7d81375204a56ec>    3791
           wifid <1e99f4977ee43d93ab83f5b4b4b3b95b>     473
       lockdownd <0095f750159533739e1f21d40733b2cc>     361
          powerd <133b7397f5603cf8bef209d4172d6c39>     276
CommCenterClassi <b923f5c5355d34cd9f2a01b8230515e3>     454
         syslogd <7153b590e0353520a19b74a14654eaaa>     149
     SpringBoard <8a3476a1ccde31e9a779449383233fa8>   15418 (active)
         configd <ee72b01d85c33a24b3548fa40fbe519c>     452
         notifyd <f6a9aa19d33c3962aad3a77571017958>     254
  UserEventAgent <dc32e6824fd33bf189b266102751314f>     672
         launchd <5fec01c378a030a8bd23062689abb07f>     176
**End**

Answer 1

I can't explain why you're getting these low memory logs, or whether they really mean anything serious. But I can explain some of what's listed in the log.
You're right that storage and memory (RAM) are different; this is just as true on an iOS device as on a PC or Mac. In your case, you have an iPad 3rd generation, which comes with 1 GB of memory. The low memory log is intended for developers, and the "pages" have nothing to do with web pages. They are "memory pages", small fixed-size blocks of memory which are managed by the operating system. The OS divides the entire memory of the machine into these pages and parcels them out to running applications. (This is normal practice on pretty much any modern computer system.) In iOS, these pages are 4 kilobytes in size, so your machine has a total of 262144 pages of memory (1 GB divided by 4 KB). A small fraction of these pages will be reserved by the operating system for its own needs.
The list of processes at the end of the log shows what was running on the system at the time. It includes running user applications as well as various background system services which are hidden from the user. The column "Count resident pages" lists how many pages of memory each running process was currently using. Facebook is the largest process, using 48165 pages.
The section above the list of processes is a breakdown of the memory by how it's being used. The relatively low number of "Free pages" is not unusual; free pages are memory pages which are kept completely unused, just in case something needs extra memory, and most modern operating systems try to keep as much memory in use as possible. After all, if you've paid for the memory in the system, you want it to be doing something useful. If some process needs more memory, but there aren't enough free pages available, the operating system will check other memory pages in use to see if any of them can be freed up somehow.
As for the rest of the breakdown, "active pages" shows pages currently in active use by some process (meaning that the process has used them very recently), and "inactive pages" shows pages which are in use by a process but which haven't been referred to very recently (these might potentially be freed up). "Wired pages" are memory pages which are currently being used by the operating system and cannot be freed under any circumstances. While it's normal for some pages to be wired, a large number of them may make it harder for the operating system to find enough free memory. "Purgeable pages", on the other hand, are pages which it's perfectly OK for the operating system to free whenever memory is needed.
Unfortunately, I can't figure out what "Throttled pages" refers to. It has something to do with iOS's memory management, but I can't find an explanation of the terminology.
If any of this seems opaque or obscure, I apologize. Operating system memory management is a very complex topic, but I tried to keep this discussion reasonably understandable.