Recommended content can be disabled in the settings menu, and then fortunately goes back to showing your own books there instead.
Special offers appears on the sleep screen and as a small footer in the library view. Most people do not find it intrusive, especially since it most certainly does NOT appear while you are reading.
The only reason why I don't like the special offers? Is because if I hadn't gotten rid of them, I couldn't use the
screensavers hack (requires
jailbreak) to make the screensaver show the cover of the book I am i the middle of reading.