They are somewhat alike. You may buy a book on-line based on how the cover looks, what others say about it. Or worse, what publisher says. Then as you start reading it you may find it isn't for you, or it takes a while to grow on you, or you immediately love it. With dating on-line one often goes at first by appearances. Then you read what the person has posted. Truth? Lies? You start a relationship on-line. It may fizzle out quickly or you stay with the on-line correspondence trying to determine if you want to meet this person. Perhaps you feel an immediate connection, or you struggle to find one. The anticipation may build until you meet the person. Then you may be disappointed, thrilled, or find the person just so-so.