[The requirement that] the allegedly deceptive email caused the adverse effects listed . . . appears to have evolved as an artifact of courts' paraphrasing each other, without an explicit analysis of what, in reality, would be required to show causation.

Congress set up CAN-SPAM with a flimsy definition of what constitute an IAS (ISP).  It includes throwaway language in CAN-SPAM that only "adversely affected" entities can bring suit.  People come along and file suits even though they pretty clearly lack any viable business activity (Gordon).  As a result courts give teeth to the "adverse effect" requirement, requiring harm different from harm suffered by the typical end user.  In this case we seem to have an entity that doesn't fall into the Gordon category, but it's clearly a small small ISP (and based in Humboldt county to boot).  Assuming it received some non-CAN-SPAM compliant messages, it should have a claim under CAN-SPAM.  There have been plenty of cases where larger ISPs with expensive experts go into mind numbing detail about the costs of their anti-spam efforts and speculate as to the per message cost imposed by spam.  But no one is ever able really to pin point the increased cost of one particular message.  Maybe that's why Congress included a statutory damages provision in the statute.  From a policy standpoint the decision seems to create a structure where larger/more established ISPs can sue because they will have more sophisticated anti-spam efforts in place and will be better able to answer the question of the cost imposed by any particular message (granted with a lengthy piece of speculation from an expert).  That's an odd outcome from CAN-SPAM, particularly since Congress did not impose any sort of size requirement for an ISP in order to be able to sue. 

At the end of the day it's not clear that summary judgment was appropriate, particularly on the basis of no adverse effect.