Computer giant IBM has sued online shopping pioneer Amazon for building its internet consumer empire partly on the back of IBM's ideas.
Like other tech firms, IBM takes its patents very seriously
Amazon is facing two suits for patent infringement in a Texas court.
IBM said its patents covered such issues as offering of product recommendations - a key part of Amazon's sales strategy.
It had been trying to offer Amazon a licensing deal since September 2002 but had received no response, IBM said.
"IBM's property is being knowingly and unfairly exploited," IBM senior vice-president Dr John Kelly said.
Amazon has yet to comment on the allegations.
The lawsuit lists five areas where IBM says Amazon "has wilfully infringed and continues to infringe on a number of key IBM patents".
IBM chose to present the case in Texas because certain courts there are perceived as being more responsive to claims of patents violation.
IBM holds more than 40,000 patents worldwide and many third parties license its intellectual capital as part of their products and services.
"When someone takes our property, without our permission through a licence, we have no option but to protect it through every means available," Dr Kelly said.