Include LOTS of pictures! People love to look at pictures. That will help to increase the interest.

Also, consider using an e-mail group like Yahoo Groups to communicate with your family. Google/G-mail also has groups. My family has had a Yahoo group for several years now, and we are up to 130 subscribed family members. It has been VERY effective in getting information out there. We now only mail out reunion letters to those who are not on the Yahoo group and don't have access to e-mail. That has definitely helped our postage costs. For an example, see http://groups.yahoo.com/group/reedpuryearfamily/

Perhaps if you set up a group for your family, you can really encourage people to check out the family's website and participate. Sometimes we have to do a little pushing....

Good Luck!
Mel