We can invite members to one site in Alfresco.

It is easy and convenience to share the sites. But currently the problem in Alfresco is that it takes long time (around 1min or more if you want to batch invite friends to your site)  to finish the invite process. After clicking invite button, the backend will send out the emails. It is in one thread! So we have to wait for the SMTP server finishing the sending.

It is not friendly here.

BTW, we can set the SMTP server in Alfresco by referring to below URLs:

http://wiki.alfresco.com/wiki/Configuring_Email_for_Alfresco

http://wiki.alfresco.com/wiki/E-mail_Configuration

http://wiki.alfresco.com/wiki/Repository_Configuration