For our wedding website, I was able to grab the domain cakeandfireworks.com... which I'm tempted to keep even after the wedding, but I have no idea what I would use it for! I chose to host the site through squarespace because it's the service I use for this blog and I'm comfortable/familiar with it.
The initial design only had pages for Our Story, Accommodations, Activities, and Pre-RSVP. The design borrowed heavily from the Save the Date card design as you can see.
The Pre-RSVP included a nifty form widget that Squarespace offers. When people fill it out, the results automatically populate a spreadsheet over at google docs. That might not sound super impressive, but it made me feel extremely organized!
Later on, after the invitations were finished, I uploaded PDF's of the planning booklets we'd included with our invitations. I also replaced the Pre-RSVP with a full RSVP form that had a check list of all the optional activities we wanted guests to consider. I added a "How to Book" page with all the contact information for Disney Weddings, Dining Reservations, park ticket prices, etc. and a Registry page (even though we don't really have a traditional registry and aren't asking for gifts).
In addition to our wedding website, I created a Facebook Group so that guests could virtually meeting and communicate directly between each other to help facilitate things like room sharing and carpooling. I'm hoping to make this social element more robust so that guests who couldn't attend our wedding are able to participate and follow the goings-on if they want to.