The iPad does not need windowed apps. The screen is simply too small too use windowed apps. Back in old fashioned days, when a 14 inch square VGA monitor was a luxury, computer users tried to sandwich two running apps onto the same screen. The monitors were just not large enough. Either the windows would be smooshed vertically or two windows would be placed side to side, with half the material off screen. We all wanted larger monitors or dual displays, but the former was not affordable and the latter was not possible. It was a different time.
On the iPad, these multi-windowed use cases are not possible. The screen size is simply too small. A single letter sized documents will fit full size on the iPad's screen, assuming the margins are set at 1 inch all around. Two documents, however, are impossible to see on the iPad's small screen. The resolution of the iPad is high enough that you could shrink the text small enough to see two full documents side by size, but you would bust your peepers trying to read it. Conclusion: comparing documents side-by-side requires huge displays or dual displays, and the iPad has neither.
For the second use case, collecting research notes, two note taking apps present a partial solution. PaperHelper comes with a split screen interface: browser on the left and text editor on the right. Either side can be resized to full screen. The text editory is text only, no images. (A similar app, Knowtilus, has a text editor screen above the browser screen.) Pento has unique “graber” tool that opens a full screen browser window. Any text or images selected with the graber tool can be placed on the notebook page. However, notes are shared as one page image files, not a mix of text and images. Like the fabled Hobson's choice, multiscreen notetaking apps on the iPad are sadly text only or image only.
Just as I started writing this, I found an announcement from Evernot that the Dolphin browser for iOS has integrated Evernote note taking. On a PC browser with Evernote, you can select both text and images and make a note out of them. The notes sync with Evernote on the web, not locally, and cannot be combined with existing notes. (But notes can be combined in the Evernote application.) Even with these limitations, Evernote integration with Dolphin looked promising. Unfortunately, it was not. Dolphin will either save a clipping as text only or an annotated clipping that is an image only.
The fallback for the iPad is the old copy and paste. At least switching apps on the iPad is easy enough. What I would like to have is a browser for Evernote, or an app like Pento that will share notes in a format that supports texts and images. A clever app could also combine two documents into one for comparison purposes. On the PC, there are plenty of apps that let you input text in particular fields and then spit out a finished document. This kind of app would be perfect for a single window device. Alternatively, Apple could expand iOS to include a pull out notepad similar to the pull down notifications menu. With hundreds of thousands of app, there must something out there to maximize single window use on the iPad.
Oddly enough, or ironically enough, Blogsy can handle text and pictures notes in one app. Blogsy includes a browser, and images, text, and links can be copy or dragged to the Blogsy editor. The browser is only half the screen size, but it works. Notes cannot simply be saved as a PDF or document formate, but whole notes can be copied into another application, such as Evernote. The material to the left was copied and pasted directly from Wikipedia for demonstration purposes. In Yet a nother twist of Irony, however, this actual post has been incredibly difficult to create with Blogsy. So while Blogsy has a hidden use as an iPad research machine, Blogsy is not so useful for its stated purpose, creadting blog posts. The iPad giveth and the iPad taketh away.