launched Cambridge Core Share, functionality to allow users to generate and share links with free access to selected journal articles, an early sign of the press's commitment to open research. In 2020, partnered with online library Perlego to offer students access to digital textbooks. In 2021, the press acquired CogBooks. The technology adapts and responds to users, "recommending course material needed to optimise learning". In 2021 the press began migrating its website onto Drupal. Controversies Tax exemption controversy In May 1940, CUP applied to the Inland Revenue for the exemption of its printing and publishing profits from taxation, equivalent to charitable status. After a November 1940 Inland Revenue hearing, CUP's application was refused "on the ground that, since the Press was printing and publishing for the outside world and not simply for the internal use of the University, the Press's trade went beyond the purpose and objects of the University and (in terms of the Act) was not exercised in the course of the actual carrying out of a primary purpose of the University". In November 1975, with CUP facing financial collapse, CUP's chief executive Geoffrey Cass wrote a 60-page "preliminary letter" to the Inland Revenue again seeking tax-exemption. A year later Cass's application was granted in a letter from the Inland Revenue, though the decision was not made public. After consulting CUP, Cambridge's 'sister' press, the giant Oxford University Press presented their own submission and received similar exemption. In 2003 OUP's tax-exemption was publicly attacked by Joel Rickett of The Bookseller in The Guardian. In 2007, with the new 'public benefit' requirement of the revised Charities Act, the issue was re-examined with particular reference to the OUP.<ref>Tom Tivnan (2007). "Charities review could hit publishers". '"The Bookseller.</ref> In 2008 CUP's and OUP's privilege was attacked by rival publishers. In 2009 The Guardian invited author Andrew Malcolm to write an article on the subject. Alms for Jihad In 2007, controversy arose over the press's decision to destroy all remaining copies of its 2006 book Alms for Jihad: Charity and Terrorism in the Islamic World, by Burr and Collins, as part of the settlement of a lawsuit brought by Saudi billionaire Khalid bin Mahfouz. Within hours, Alms for Jihad became one of the 100 most sought after titles on Amazon.com and eBay in the United States. The press sent a letter to libraries asking them to remove copies from circulation. The press