As Learned Publishing celebrates its 30th birthday, the April issue opens with an editorial celebrating this milestone. “Question all assumptions” looks at the big questions that the journal has addressed during its history, and asks where we might be going in the future. The other articles in the issue continue the dialogue with original research on why authors publish in “predatory” journals - and an opinion piece asking if it is “Time to stop talking about predatory journals’? There is research on the use of DOIs in China, and looking at how - and if - citation counts can be anticipated, and the OA landscape of natural and social sciences. Along with several opinion pieces – one questioning whether the future of publishing is revolution or evolution; a case study on machine learning; and a discussion of the website’s role in content marketing – the issue is packed with useful content and a great start to our anniversary year.