What are some alternatives?
When comparing Collaborizm and Attendize Event Ticketing, you can also consider the following products
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Eventbrite - Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
DownToMeet - DownToMeet is a platform to organize, find, and attend group events.
Ticket Tailor - Ticket Tailor is an easy to use event ticketing platform that puts you in control.
pretix - pretix helps you to sell tickets for your event in an easy way. It supports multi-lingual events and provides a wide range of features
Agorakit - Agorakit is web-based, open source groupware for citizens.