Evite

Evite is a social-planning website for creating, sending, and managing online invitations.

Evite was launched in 1998. The website is a free, advertisement-supported service. It was acquired in 2001 by conglomerate IAC/InterActiveCorp. In 2010, Liberty Media acquired ownership of Evite from IAC.

An event organizer creates an online invitation through the website via a simple interface. This online invitation is colloquially referred to as "an Evite". The host enters e-mail addresses of prospective guests and Evite sends e-mails to the guests. Each guest is in one of four categories: "Attending", "Not Attending", "Maybe", and "Not yet replied". Guests move themselves from the "Not yet replied" category to one of the three "replied" categories and can write additional comments.

The HTML page for the invitation may have various stylistic features chosen by the inviter. These include setting, color, layout, and renaming the four guest categories.

Hosts may opt to send guests updates when other guests RSVP for the event, or when the event details are changed.

According to Mashable and Venturebeat, Evite has threatened to sue San Francisco-based startup and competitor Socializr (acquired by Punchbowl.com in November 2010) due to alleged copyright infringement.

...
Wikipedia