@@Pablou It gives guests all the information about your wedding... (so questions are answered and they aren't bugging you while you are trying to plan).
You could include how you met, your engagement, info about your resort, travel info, how to book, travel agent info, pictures, reception info, rsvp details, etc...
Mine has kept my guests informed about everything thus far! I keep it updated.
You would just include your url on your invitation (probably at the bottom).