I just sent this message to the PR department at Netflix:
I have been a Netflix customer for several years and am generally very happy with the service. Today, however, I discovered that Netflix only allows users to have a maximum of 500 movies in their queue. While 500 would seem to be quite a few, I just reached that limit and would like to be able to add more.
One of the things I like about Netflix is that the queue enables me to easily maintain a list of all the movies that I hope to see someday. I realize that it will probably take several years for me to see all of the movies now in my queue, but I certainly intend to live that long. Moreover, customers who have long movie queues are likely to be customers that Netflix can count on retaining, so I think it would be in your interest to allow us to have as long a queue as we want. Disk space is incredibly cheap these days, so I can't imagine that the 500-movie limit is saving Netflix any money. I'd therefore recommend lifting it.
I had an exchange about this with Doug Whitfield on Twitter, who thought "they have to limit it somewhere. 500 seems reasonable to me. Yahoo! has strange limits too. Better safe than sorry, I guess." I thought about that a bit, and I don't think it holds up under scrutiny.
For starters, Yahoo! is mostly a free service, whereas Netflix makes its movie queue available only to paying customers. Yahoo! actually needs to put some limits on the amount of storage space, bandwidth and other resources that it gives away. On Netflix, howeer, the subscription fee would weed out users who might want to do something frivolous or wasteful with their queue. Moreover, I don't see much risk in practice that someone would want to abuse the queue. All the queue lets you do is compile a list of the movies you're planning to rent from among the 100,000 DVD titles in the Netflix database. What incentive could there be for someone to abuse that? There's no way that someone could use it as a platform for spamming or for hosting porn.
I'm trying to imagine a worst-case scenario here: Someone writes a bot that adds all 100,000 titles to their Netflix queue. If they did, it would use maybe a megabyte of storage, tops. I don't see how that would be a problem for Netflix. Okay, now let's suppose that someone wants to run that bot on multiple Netflix user accounts. To do so, of course, he'd have to pay $4.99/month for each account, so Netflix would probably be making money on the deal.