Jay, Online dating has become quite mainstream in the last dozen years. I know quite a few people who have found long term relationships and I've had some short term (six weeks-four months) success myself, though I ascribe my inability to find a long term relationship through them more to the fact that there are very few women in my age bracket that I find attractive, that most younger women looking on the "mainstream" sites are primarily looking in their own age bracket and most of those near my age, sadly, have considerable baggage. If I recall from your other thread, you are some 20 years younger than I am and, as such, you're much more likely to be successful than is someone my age.
Match.com is probably the oldest and most successful and has a membership fee. The one that I'd recommend as they have matching algorithms that are quite sophisticated is okcupid.com. These sites are both tailored for people looking for "traditional" relationships.
Good luck.