A new version of Mobile Safari has been announced for iOS 5. Two significant featured were demoed at WWDC. These are Reader and Reading Lists.
Reader allows you to review online articles without the clutter associated with many websites.
Reading List lets users download articles later for offline reading.
In other words, Mobile Safari could very well kill Instapaper, which already offers these features.
Finally, for iPad users tabbed browsing is now available. This helps you keep track of multiple web pages and switch between them easily and quickly.
Like iOS 5 itself, the new Mobile Safari is currently in beta and will be available this fall.