when did online dating start? I'm looking not merely for a date (pun
intended), but also for information on the people who started trying
to get people to meet online and why they did it (it started within a
small some religious group, right?)

The first chronological match for "online dating" in Google Groups is
1990, in an advertisement for a Long Island dial-up bulletin-board
service:

http://groups.google.com/groups?q=%22online+dating%22&start=30&hl=en&lr=&ie=UTF-8&safe=active&scoring=d&as_drrb=b&as_mind=12&as_minm=5&as_miny=1981&as_maxd=26&as_maxm=7&as_maxy=1995&selm=N7Je78w164w%40dorsai.com&rnum=36.

The first mention of a WWW dating site is from June 1995, but a post
claims that it was a fake:

http://groups.google.com/groups?q=%22online+dating%22&hl=en&lr=&ie=UTF-8&safe=active&scoring=d&as_drrb=b&as_mind=12&as_minm=5&as_miny=1981&as_maxd=26&as_maxm=7&as_maxy=1995&selm=8AB41F4.0F0A000169.uuout%40compudata.com&rnum=5