I suspect most Online Dating Sites offering compatibility_matching_methods like
eHarmony
True
PerfectMatch
Chemistry
YahooPersonals (WeAttract’s tests)
CyberSuitors
Ulteem
Parship
Plentyoffish Compatibility Predictor
MatchWise
and others
are using self_adjustment multiple/simple linear/nonlinear regression_equations to predict compatibility between prospective mates.

BUT

There are more than 900 “Online Dating & Social Networking Sites” at the United States and Canada, and top 10 Online Dating sites have 80%/85% of actual market.
If you add net paid subscribers of all U.S. dating sites, perhaps the total is less than 5 million persons!!!

What dating sites are doing / will do to court the other U.S. 87 million singles not seriously dating online? They need to offer GREAT INNOVATIONS, but …. they will definitively come from new discoveries on Theories of Romantic Relationships Development with:

* 16PF5 NORMATIVE test as main personality test (available in different languages)
* powerful math equations (not more regression equations!!!!)
specifying:
- Ensemble: the whole set of different valid possibilities.
- Precision: like 0.00000001%
- Main Matching Equation: like an adapted quantum mechanic equation.
http://en.wikipedia.org/wiki/Braket
- How the compatibility predictor is expresed: like Client#X to Client#Y == 92.55033557%
- Average number of “compatible real persons” for one person over the entire database: like the 3 most compatible in 100,000 persons database or the 12 most compatible in 1,000,000.

Regards,

Fernando Ardenghi.
Buenos Aires.
Argentina.
ardenghifer@gmail.com