The Inforarium was a data bank, described by the Eleventh Doctor as "the greatest source of illicit information in recorded history". This information was stored in twelve levels of reality, making it near-impossible to hack and impervious to erasure.
It contained information on the Doctor, which was sold to the Daleks, the Cybermen and the Sontarans, which the Doctor took issue with. Being unable to delete the content, he therefore "memory-proofed" it, adapting Silence biology to his own needs. This made anyone who learned anything of him through the database forget that information soon after. (HOMEVID: The Inforarium)