With regards to Safari 5’s new Reader mode (whose availability is subject to unknown and quite whimsical heuristics):

1. Palatino is rarely appropriate for online reading. Most serif faces not specifically designed for screen use should be avoided, in fact; sub-pixel anti-aliasing only buys you so much.
2. Setting body text fully justified is inevitably a bad idea online. Not only does Safari lack hyphenation, but proper hyphenation is language-dependent anyway. More to the point, the fixed column size in Reader creates rivers of white space in many documents, even for users who don't increase the text size. Those who do are doomed to unreadable crap.
3. Even if Safari did support hyphenation, you should still avoid justification, because the screen resolution simply isn't fine enough to do it well. Not even the magic pixie dust in the pixels of the new iPhone display give sufficient resolution to produce both crisp Palatino and evenly justified columns. There's a reason that 1200dpi is considered low for printing actual books.
4. Open up the stylesheet; hiding it inside the Safari bundle forces people to choose between invalidating your code signatures and putting up with your poor design choices.
5. Allow the new Extensions code to load into Reader pages.

While I’m here, every version of Safari has suffered from the problem that right-clicking a link disables all mouseover events on that page until you click somewhere else. Even the builtin cursor change on mouseover is disabled. This remains true in this latest major revision. Has no one else ever told you about it?