As long as you don't lead anyone on, it's fine to dabble in serial dating. A first date doesn't carry any long-term committments, so think of it as social networking.
Casually dating different types of men/women can help you better understand what you are looking for in a significant other, develop a new interest (Ie: music, arts, a new kind of food you haven't tried before), learn something new about yourself or make a new friend/group of friends.
And you might meet someone special through that new group of friends!