Canonicity
Although they are produced by the BBC, the canonicity of the material on these websites is unclear. While parts of "Who is Doctor Who?" and the UNIT website are consistent with the events of the episodes as broadcast, other parts are not. For example, the UNIT website dates the climactic events of "Rose" to March 26, 2005 (the date of broadcast). However, a poster clearly seen in "Aliens of London" states that Rose Tyler had gone missing on the night of March 6.
The "History" section of the website claims that UNIT was formed in 1968 following the "London Underground" incident, a reference to the events of The Web of Fear. This seems to establish the events of the serial as happening in that year, although the dating of the UNIT serials is a long-standing controversy in Doctor Who fandom. See UNIT dating controversy for more details.
In addition, despite the implication that at the end of "Father's Day" the attack of the Reapers did not happen due to changes in history, "Who is Doctor Who" featured photographs that showed the attack. The UNIT website also referred to a report about the incident, although the Doctor claimed no one would remember it.
The Torchwood website features audio and video participation of the actors from the series, usually onset. In one instance, PC Andy refers to his surname as "Davidson", which had been noted in the novels (of debatable canonicity) but unmentioned by the TV series. This development lent some credibility to the surname.
Read more about this topic: Doctor Who Tie-in Websites