The concept of the Meetup.com is very nice, you can join as well as create a group which intrest you and plan and then organise a meetup. You can learn from experience of the people from the same field or from people whose interest is same as your’s. Meet new people with similar hobbies or interest at time and place which every one of you is comfortable.
The only drawback of meetup.com is that the success or failure of the meetup is entirely depend on the team leader. If the team leader is not capable of handling team members and make them come to an conclusion then the meet will flop. I have attended 3 to 4 meetup out of them only one was successful and enjoyed a lot during that meetup.
Overall if you want to meet new people with similar interest or hobbies and learn as well as spend time together then this is your place. I would recommend it to everyone try it once.