Microsoft did the same thing with respect to SPF, asserting that they had patents filed for that had claims that SPF and related sender control technologies cou

Microsoft did the same thing with respect to SPF, asserting that they had patents filed for that had claims that SPF and related sender control technologies could have infringed upon but wouldn't assert exactly what those patents were or exactly what claims would be targeted. It severely retarded the marketing, uptake and discussion around email sender control, and was a huge distraction.