When browsing certain sites like Flickr on the iPad, you may be frustrated by an apparent bug in Safari that causes scrollbars within elements on the page to disappear. This can make it impossible to perform certain functions.
For example without the scrollbars in the photo selection window, it's very difficult to select the right images to add to Flickr's Groups.
It turns out this behavior is not a bug, it is by design. Scrolling these elements on the iPad is done using a two finger scroll. Hold two fingers together and brush up and to the right across the area you want to scroll. If two fingers does not seem to work, try three. When it is working it is quite easy and smooth.