How about let people invite others to your board? This resource will allow users (members and/or guests) to invite their friends by filling a form that will be sent via email. Form will be processed and email sent via ajax but if the user opens the form on a new page/tab, then a minimal "thanks" page will show after submit the form.
Groups allowed to use the form
The form won't be submitted if the email used belongs to a registered member (that wouldn't make sense to "invite" someone who already is a member from the community)
They will be asked to provide their name and email address
A captcha will be added to the form
Warning and Email Subject/Content:
The message in the form, the email subject and body are language bits so you are free to change them to whatever you want in your own Admin CP.