But Twitter users were quick to point out that the phrase "Your Mum" is often used by young people as insult or the punchline to an offensive joke.
Looking for a nice book on mindfulness for #YourMum - she'll need it after last night weeeeeey— Mollie Goodfellow (@hansmollman) March 9, 2015
The publisher was quick to acknowledge that it was possibly not the best choice of hashtag:
Thanks for pointing our #YourMum has an alternative meaning you guys! Now back to the books...— Penguin Books UK (@PenguinUKBooks) March 9, 2015
But it wasn't long before Penguin also got in on the action:
The hashtag #YourMum was trending on Twitter on 9 March, and has left some people wondering whether it was all a PR ploy:
Hard to tell whether Penguin's #YourMum was intended or not. Either way, we're all talking about Penguin. Proof will be in sales figures.— Chris Lee (@CMRLee) March 9, 2015