Online relationships/matrimonial sites have proved successful for some people, whereas others have been disappointed by them. And then, there are also people who don't feel comfortable with the idea of not being able to see the potential friend/rishta face-to-face during the communication process.
A person can be deceived/taken for a ride in both personal/face-to-face relationships as well as online relationships. The risk for deception in online relationships is greater because you can't see the other person's face/expressions, etc.
Online relationships are simply another option for people to make connections and find a spouse. Whether one wants to seriously consider this option or reject it depends upon personal preference.