According to the page, this is the data that is stored on the chip:

=== CUT === In addition, this memory chip collects a limited set of information about the usage of the product, which might include the following: The date when the toner cartridge was first installed The date when the toner cartridge was last used The number of pages printed using the toner cartridge Page coverage Printing modes used Any printing errors that might have occurred The product model === CUT ===

I don't like that they collect this info, but I don't see any really scary information mentioned there?

Whether I trust HP that is all they store and recover is an entirely other matter ;)