I tried meetup.com meetings in London and Amsterdam. The concept of meetup.com should have been perfect to meet women. Those meetings are sorted by theme. Theoritically, Meetup.com events should have been a great way to meet women if you are new in a city or if you visit a city.
I extensively tried meetups and found it was not a place to find a date. When I stayed in London as a young professional, I noticed that women of my hostel or my workplace were much more interesting for a date than what I could find at a meetup.com meeting. For your information, I met beautiful women at my workplace but I never saw beautiful single women at meetup events in London and Amsterdam.
Profiles of women are very specific. If it is a meetup with a theme that is popular to women, you may only find housewives and early grannies. If it is a meetup with a more general theme, you will find a ratio of 7 men to 3 women. Plus, there were lots of men who were also looking for a new date. Consequently, when there is a pretty woman in a meetup, she is surrounded by several men.
In other words, it is just like going to a nightclub except some people may ask you to become their friend and ask you to find a job for their girlfriend/wife….
In conclusion, there are way better networks of people than meetup.com to meet women.