The ruling on Thursday does not free Spamhaus from having to pay monetary damages in the case, however.
Spamhaus was ordered to pay an US$11.7 million default judgement to e360insight in October 2006.
E360insight had claimed that Spamhaus had unjustly labelled the marketing firm as an origin for unwanted email, and had placed the firm on its Registry of Known Spam Origins (Rokso).
Spamhaus claimed that the US court had no jurisdiction over it and refused to proceed with the case.
As a result, the court entered a default judgement and awarded damages based on e360insight owner David Linhardt's own estimates on prior and future damages from the blacklisting.
That estimate, said the Court of Appeals, was not properly examined or audited by the courts before being awarded by the lower court.
"Linhardt's affidavit is a conclusory statement of the lost value of his business, based largely on his calculations of lost future profits," declared the court.
The statement provides a list of businesses involved in "actual and pending contracts and a total calculation of his calculation of loss, but says nothing about the status of his relationship with those businesses before e360 was listed on the Rokso".
The judge ordered the lower court to conduct a more thorough investigation into the damages.
The court also overturned an injunction that would have forced Spamhaus to remove e360 from its blacklists and post an apology on its website.
US court grants Spamhaus reprieve
By Shaun Nichols on Sep 4, 2007 7:26AM