I think it's OK to meet someone on the internet, and become friends thru writing...but...
I don't think it's possible to truly "fall in love" with someone over the internet, until you meet in-person, and in reality.
Love is a big, wide word, but "true love"...commitment and sacrifice for each other, over many years...requires knowing someone in-person, and experiencing reality with her/him.
Email is no substitute for this...but I do think it can be a good start.