Fall in love... no. Become attracted to someone... yes. We should reserve our love for the people who have earned our love, i.e., someone who we have spent time with (in person), and someone who has proven that they deserve our love. Just my opinion...

One time and this lasted 2 years ! I think that if we're open-minded, we can to find nice people on internet for an amazing relationship

Yes I did. It was an amazing experience :)

In American English, you can use both the present perfect and the simple past in some contexts. For instance, "Have you lost your keys?" and "Did you lose your keys?" are both acceptable in conversational American English, although, "Did you lose your keys?" is the more natural sounding and more common way of asking it in conversational American English, in my opinion. In a question that asks whether you have ever experienced something at least once though, I think we always use the perfect tense. So I would ask, "Have you ever fallen in love with someone on/through the Internet?" Anyhow, yes, I have fallen in love with a number of people online. In fact, I met the person I am dating right now through Facebook. :)

Love does not exist