This setting on the event list form will control what people have to type on their browsers to reach your list.
The link to your event list will always look like this: eventida.com/list/YOU_SET_THIS
Recommendation for Public Lists:
The URL name should match your twitter handle or facebook handle.
EXCEPT: when you or your webmaster embeds the list on your website - you can share your webpage URL. For example, if you have a website mysite.com you will likely embed it on a page called "Events" and the URL will look like mysite.com/events. Consult your webmaster or content manager for details.