Maybe 2, because I really don't have enough time to juggle everyone, usually I will hang out with them, and if we kiss and it's good and I get that vibe that I wish they were my boyfriend then thats when I decide. But it shouldn't be much of a decision by that point
Whenever I have dated, whether online or conventionally, I have only dated one person at a time.
My experience with online dating was with eHarmony. I dated matches that I received serially. Seven months into my online dating experience, I was matched with the woman I eventually married. From the point of our first date, I've dated no one else.