Have there been any studies done as to the degree of anonymity obtained from using these remailers? (I haven't been able to find any.)
Have a look at: David Chaum: Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms, Communications of the ACM 24 (1981) 2, pp 84--88, http://world.std.com/~franl/crypto/chaum-acm-1981.html Wei Dai: Traffic analyzing Chaum's digital mix, 1995, http://www.eskimo.com/~weidai/traffic.txt Lance Cottrell: Mixmaster and remailer attacks, 1995, http://www.obscura.com/~loki/remailer/remailer-essay.html
And does anyone know of any studies being done in determining whether or not content-based analysis - diction and language - is a reliable way to determine identity?
Thomas Horton: Stylometry. In: R. Asher (ed.): The Encyclopedia of Language and Linguistics, Pergamon Press, 1994, pp 4383--4385. Joseph Rudman, David I Holmes, Fiona J. Tweedie, R. Harald Baayen: The State of Authorship Attribution Studies, 1997, http://www.qucis.queensu.ca/achallc97/papers/s004.html A somewhat related area: Ivan Krsul, Eugene Spafford: Authorship Analysis: Identifying The Author of a Program, 1997, ftp://coast.cs.purdue.edu/pub/COAST/papers/krsul-authorship_analysis_NISSC.ps.Z