Messages, platform, users, meta

Hi,

I want to use wordpress as an (interactive) platform for 60-users. The users must be able to add events (all in one calendar) and post messages. When a user posts a message does the other users get informed by email?

I also want that users can register when vistiting the website. A added the widget meta but there are some links like www.ads-software.com that I want to delete. Is this possible? I also want the link register but I can’t find it anywhere. Is there someone who can help me with this?

Thanks in advance