From smart toasters to fitness collars for dogs, we live in a world where everything around us is gradually being connected to the internet and fitted with sensors so that we can interact with them online.

Many people worry about the privacy risks of using these devices because they may allow hackers to listen to our conversations at home. But the contracts for using them are so long we don't understand which other rights we might be signing away.

During research for my book, I found that using Alexa's voice command triggers 246 contracts that we have had to accept in order to use it. These contracts transfer our rights and data to countless, often unidentified, parties. For example, they frequently refer to "affiliates".

Despite months of research I wasn't able to clarify who these affiliates are or even whether these affiliates are subsidiaries or advertisers. Of the 246 contracts, I focused on those that are most likely to be relevant to smart speaker Echo's users. I found they are on average as long as Harry Potter and the Prisoner of Azkaban (317 pages). Not exactly a light read.

Data analysis company Statista found, it would take an hour and a half to read Apple's terms and conditions for creating an Apple ID. And that's assuming you don't need to pause to check the text's meaning.

Using the Literatin plugin, a Google Chrome extension that assesses the readability of text, I found these contracts are as readable as Machiavelli's 16th-century political treatise, The Prince.