Members of Organize Us can transition through a variety of states. 
In most cases, when a member is first invited, they will be displayed as "eMail pending validation".  Once the member has validated their email address, this will no longer be displayed.  If the email address is not valid, or becomes invalid because of numerous bounces, the member state will be set to "eMail Invalid".  The member can change this by validating their email address again. 

These states are intended to help other members know if they have invited the correct member.  For example, if the email address was invalid, it could be because the Organizer invited the wrong person.  Displaying the email as invalid allows them to notice this and correct the problem by inviting the correct email.

eMail Pending Validation:
All new members will have this state before they have validated their email address.  Members that have this state will be sent eMails from Organize Us.  If the emails are bounced a certain number of times in a certain period then their status will be changed to eMail Invalid.  Members with this status must validate their email address by going through the signup process before being able to access Organize Us.

eMail Invalid:
This state represents members whose email addresses have been marked invalid by their email service provider.  This state is used when emails sent from Organize Us have received a certain number of permanent failures from the server responsible for the email address.  Members that have this state will not be sent any emails.  They will not be able to login until they have validated their email address.

Disabled:
When members are no longer interested in using Organize Us, they can set their account to be disabled.  This state is selected by the member and is voluntary.  Disabled members will not be sent any emails from Organize Us and will not be able to login until they have gone through the signup process again.

Suspended:
Suspended members are members that have had their account suspended by Organize Us for some reason.  This is most likely because of a violation of the terms or use, but can be done for other reasons.  Members whose accounts have been suspended will not be able to access Organize Us, even if they go through the signup process again.  Members who are suspended should contact support for more information on why their account was suspended.