has turned red and features a link to the charity's feed together with the line "1 Dec is World Aids day. Help turn Twitter (Red). Follow to find out how."
Additionally Twitterers can change the colour of their tweets to red by using the hashtag #red.
(Red)'s Twitter page also features Nike's "red" football laces, which launched yesterday (30 November) with all of the profits from the campaign going to the charity.
The laces were launched in London's Niketown store with Bono and footballers including Chelsea's Joe Cole, Didier Drogba and Arsenal's Andre Arshavin.
to encourage members to change their profile pictures to a (Red) logo as well as share a video about the low cost of the treatments it takes to keep patients with HIV alive.
Google.com is also running a link on its home page by running a red Aids ribbon linking through to various charities connected with fighting the disease.
However Google.co.uk, which has celebrated events such as the anniversary of Sesame Street and Halloween, has not made any alterations to its homepage for the day.