Get Me Some dot com
Over lunch L. and I invented a new web service, soon to become part of the LazyWeb. You insert a metatag into your page that indicates whether you have a partner or not. Our service aggregates this info, along with similar info of people, say, on your subway line, in your social network, your blogspace, your blogroll, etc.
If in the unfortunate case that you separate from your partner, you check http://www.getmesome.com/ and you'll see related people who are in the same scenario as you.
Aside: We had a good laugh over this, but I'd be lying if I said I didn't think about how practical it would be. On another level, the laughter is at the expense of the current social networks analysts, who are finding a lot of connections that may be devoid of any practical meaning. GetMeSome.com's connections aren't strong enough to be an indicator of compatibility, or even simple attraction. And yet, it does get you thinking about dating services of the future.