Editing Spamming (section)

===General costs===
In all cases listed above, including both commercial and non-commercial, "spam happens" because of a positive [[cost–benefit analysis]] result; if the cost to recipients is excluded as an [[externality]] the spammer can avoid paying.{{citation needed|date=May 2021}}

'''Cost''' is the combination of:
* Overhead: The costs and overhead of electronic spamming include bandwidth, developing or acquiring an email/wiki/blog spam tool, taking over or acquiring a host or zombie, etc.
* [[Transaction cost]]: The incremental cost of contacting each additional recipient once a method of spamming is constructed, multiplied by the number of recipients (see [[CAPTCHA]] as a method of increasing transaction costs).
* Risks: Chance and severity of legal or public reactions including [[damages]] and [[punitive damages]].
* Damage: Impact on the community or communication channels being spammed (see [[Newsgroup spam]]).

'''Benefit''' is the total expected profit from spam, which may include any combination of the commercial and non-commercial reasons listed above. It is normally linear, based on the incremental benefit of reaching each additional spam recipient, combined with the [[conversion rate]]. The conversion rate for [[botnet]]-generated spam has recently been measured to be around one in 12,000,000 for pharmaceutical spam and one in 200,000 for infection sites as used by the [[Storm botnet]].<ref>{{cite conference| last = Kanich | first = C. |author2=C. Kreibich |author3=K. Levchenko |author4=B. Enright |author5=G. Voelker |author6=V. Paxson |author7=S. Savage | title = Spamalytics: An Empirical Analysis of Spam Marketing Conversion | book-title = Proceedings of Conference on Computer and Communications Security (CCS)| place = Alexandria, VA, USA | date = 2008-10-28 | url = http://www.icsi.berkeley.edu/pubs/networking/2008-ccs-spamalytics.pdf | access-date = 2008-11-05}}</ref> The authors of the study calculating those conversion rates noted, "After 26 days, and almost 350 million e-mail messages, only 28 sales resulted."