It turns out that HP requires its customers to enroll HP Instant Ink eligible printers into one of the Instant Ink plans, and continue paying a monthly subscription in order to be allowed to use the device.

But where's the need to come up with different plans coming from, you may wonder? HP explains: the company charges a fee based on the number of pages a customer prints each month, and the page count is shockingly monitored remotely.

Naturally, the scheme is not advertised as a rather unusual application of DRM, but a way for customers to save time and money. Still, it would seem HP has not exactly gone out of its way to explain all the consequences to those customers.

HP's terms of service also say that these eligible, internet-connected printers can be remotely modified in several ways, including by applying patches, updates, and "changes" – without notifying customers.

Another thing HP can see thanks to the Instant Ink program is the type of documents you print, identifying them by extension as Word, etc., documents, PDFs, or JPEG and other types of images.