I upgraded to Lion on my MacBook Air last week and I'm using Safari in full screen mode. One of the side-effects of this is that many text based sites are too wide for comfortable reading.
Clicking "Reader" in the address bar (or command-shift-R) drops a shadow across the page and opens an overlay containing the core text of the page minus annoying ads and other visual distractions. Really nice.
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Click here |
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and see this uncluttered clean version of the text |
The reader feature was introduced with Safari 5 as part of Snow Leopard but it wasn't until I started living in full-screen mode that the utility of this feature presented itself.