I just wanted to go ahead and add a little write up for anyone else who comes here looking to understand the differences between these two storge locations.
With previous Droids (pretty much everything before the Droid 3 if I am not mistaken) everything was automatically saved to your SD Card. If you did not have a removable sd card in your phone, you had no storage space for things like pictures, music, other files. Now they have reserved a portion of the phone's built in storage for what they call internal storage or "media area". However, you also have an external sd card which is the removable physical sd card. Note: I am referring to Mototorola phones when I mention pre-droid 3 and post. I am not familiar with storage practices of other manufacturers.
How do you navigate to each and tell the difference? That depends of what files service you are using. Here is the breakdown:
Stock file manager that is already on the phone:
1. Open your app drawer and click on the file manager app (it may be called "my files" or "file manager" etc.)
2. The stock file manager actually lays it out straight forward. You either see "internal storage", or "sd card"
3. You can move files from one to the other by simply long pressing on it and selecting either move or copy and then going to where you want to place it and select paste from the menu.
Market file manager like astro:
If you downlaod a file manager from the market like astro, es explorer, etc. you will notice that they typically do not indidcate "internal" or "external" instead you will most likely see "sd card" and "sd card-ext". The "ext" is short for external and this is the actual removable sd card. The folder labeled as just sd card is actually the internal built in storage area of the phone.
Windows file explorer.
If you plug your phone into your cpu using usb and you select USB mass storage on your device so it knows you want to share your storage with you PC, you will likely get two windows (if yu have auto play enabled) that pop up with the standard question of "what would you like to do". Once again, these two storage places are labeled differently. Each of these two storages will be given a drive letter and a name. One will likely be called MOT, this is the internal phone storage. The other should actually say "removable storage" and is the actual removable sd card on your phone. If for some reason they do not display "names" and only show you drive letters on your pc, you can go ahead and open both on your computer to take a look inside. Your phone's internal storage will have a file (near the top usually) labeled ".cache" and your external sd card typically will not have that file.
Hope this helps.
