Digital Spy...

Digital spy on Silence in the Library:
As always, 2 of them are red herrings.

-There is a Jeffrey Archer continent in the library.

-Donna tells The Doctor that she "likes a bit of Hank Marvin" when he warns her about the shadows.

-Data Ghosts are footprints on the beach - and the tide is coming in.

-The Doctor rants against reading spoilers (irony noted!)

-There are two sonic screwdrivers featured in this episode - and neither is any good at dealing with wood.

-Psychic paper is used to contact The Doctor, in combination with a kiss (but not from Donna).

-Donna flicks through a biography of Harriet Jones, but has to run away before she reaches the final chapter (although viewers see its shocking title, unlike Donna).

-A figure from The Doctor's future makes an appearance.

-A Dalek's eye stalk is brought up by The Doctor out of nowhere.

Theres also these quotes:

"The library goes on forever."

"Isn't travelling with you one big spoiler?"

"Run, for God's sake run. ******e is safe."

"4022 *****. No s***i****."

"That was the most horrible thing I've ever seen."

"The real world is a lie and your nightmares are real."

Also according to DigitalSpy, River Song instantly recognizes the Doctor, claiming that they have been to many places together - but the Doctor has no idea what she's talking about.