It's usually considered bad form to mention your wedding registry on your wedding invites themselves — it's like openly asking for gifts. These days, since news doesn't travel via word of mouth as easily as it used to, it's essential to have a comprehensive wedding website where you can list information about where you're registered, how to get to the ceremony site, accommodation information, etc. so that your guests can easily access all of the relevant information. It also saves you a lot of time by not having to answer questions all the time!