Folger Shakespeare Library, USA
Bodleian First Folio, A digital facsimile of the First Folio of Shakespeare's plays, from the Bodleian Library, UK
Discovering Literature: Shakespeare The British Library.
British Council Shakespeare Lives
British Council Literature
British Council Exploring English: Shakespeare Free online course. Improve your English language skills by looking at the life and works of William Shakespeare.
British Council Teaching English: Shakespeare's language. For those teaching English as a foreign language.
Daily Shakespeare Twitter spot
Today, this is replaced by a list of accounts from organisations mentioned in the links just given.
@LitBritish (British Council Literature)