Punchbowl - A party planning and greeting card website
Pingg - Pingg is an online e-cards and invitation maker and invitation sending platform.
Whoozin.com - Free RSVP Online | Track RSVP’s and Sell Tickets for your events and recurring meetings.
Manvite - As the name of this service suggests, the users can avail easily and simply invite rather than online summons that are blessed with flowery fonts and dabbling champagne glasses.
JustRSVP.me - Online Invitations and response tracking for weddings, baby showers, birthdays, parties, and other...
Zoji - As claimed by the developers of this Zoji, it caters online tools to aid you plan activities off-line.