I sure didn't until I visited PostalHistory.org.
'Marcophily' is the study of postmarks.
Some of the postmark societies and clubs that have links on the site's topical resources page include the Bullseye Cancel Collector's Club, The International Machine Cancel Society, Post Mark Collectors Club, The Railway Post Office Postmark Society and The US Cancellation Club.
Webmaster John Tollan of Melbourne, Australia says he's willing to put on the site information about postal history collections, covers, research, articles, etc. and add links about other postal history related websites.
For more information and to visit this interesting site, click here.