Com Score, a research firm, says Match and Zoosk, two large dating services based in the United States, saw 4.6m and 4.8m unique visitors respectively come to their American sites in November 2010.
Meetic, Europe's biggest dating service, also boasts millions of users.
Many others will offer money or pretend to be messages from companies – and they change their approaches with the seasons.
The Independent's bitcoin group on Facebook is the best place to follow the latest discussions and developments in cryptocurrency.
Another is that they are living longer, and hence more likely to look for new love later in life.