Suppose you have one browser open on the Internet copy of a web site and another open on the local copy of the new site that you are developing. You can do the comparison between the two sources to check that they agree, but if say you check another document or picture, it is quite easy to hide one of the browsers on the desktop.
Using two browser windows in the Daisy Multiple Browser makes this process much easier and quicker.
In the picture, a local and Internet copy of a web site are being compared. It is obvious in this simple example that a picture is missing.
There are lots of applications, where it is necessary to view two or more pages in this way. As screen sizes increase, it will be possible to show four 800 x 600 images at the same time, thus making taks like web site checking much easier.