You can read two WEB or PDF pages in one view, layered or side by side.
The pages load from Safari or iTunes. You can save loaded PDF file to local.
from iTunes,
Device -> Apps -> File Sharing
and select "Layered" in Apps list.
from Safari,
http://www.apple.com/
lr://www.apple.com/
Example:
√ Read different pages in one document on one view, chart and description, graph and table...
√ Pages that written in different language tile on the view.