Well, at the risk of sounding like a zealot about this

there is a lot more to it than just making online reservations. Don't get me wrong, that would be nice, but it would also be nice to see point usages, banking and borrowing information, waiting list length and position, historical personal usage, etc. Thekind of stuff Caskbill's program tracks (thanks Caskbill, I just downloaded that the other day, it looks great so far!) but from their perspective; like an online bank statement versus your personal Quicken information - it's nice to make the comparison.
I do understand the need to weigh cost versus benefit, and I certainly hope as a member they would do that and not jump blindly into projects. I do think, though, that perhaps the cost might not be as high as some think. And with more people joining DVC daily, it's not like they would have to lay off phone representatives, just not hire as many more. The whole thing that so many people do with the daily calls "extending" their stay is a great example of something that could easily be done online and save the phonelines for people that need to talk to the representatives. Let's face it, the phoneline situation is really out of control sometimes.
The whole point is customer relations. Customer relations is important, because it keeps customers happy. Yes, "they have us" as some say. For now. But it's clearly important to DVC to keep the resale market up, and with other clubs out there competing, the only really clear advantage DVC can count on is the ability to stay on grounds at Disney.