raymor

Shap is, I think, exactly right and dead wrong.
I think there are four very good reasons to control this kind of abuse, four reasons
which all help increase retention, but you have to be smart about it - or rather, you
need a system which is smart about it. I'll explain what I mean, but first, back to the
question of what is a good limit.

Another way to look at it is "what is legitimate usage?" You probably want the customer
to be able to use the site twice in a day. That's 40 minutes of whacking it in a day.
If your video runs about 5 MB per minute, that's 200 MB / day. Then add a bit extra
because happy customers are important. If someone downloads 2GB, that's 400 minutes
of video - probably more than they need in a day. If your video runs at 10 MB per minute,
you'd double the limits that you'd use at 5 MB / minute. Whatever your mix of video and
images, just figure up what someone can watch in say, an hour total for the day.

As Shap said, bandwidth is cheap, but that's not really the point, in my mind.
To me, if someone is downloading several hours of video each day, I know they
aren't watching it. At worst, they are putting it up on their own sites and probably
spreading it all over the peer to peer networks. If I don't want all of my content
out there for free, I don't want this guy downloading 12 hours of video every day.
At best, he's downloading 12 hours of video every day so that he can cancel after
the minimum membership period and keeps using my stuff for free. I want to do
whatever I can to keep him around. I think I can keep the punter around longer
by making it not quite so easy to download everything I have in a week or two.
Not by having super strict limits, mind you, but give him plenty of material for today,
then tomorrow he can gets all that he needs tomorrow. As long as he's a member
he gets what he wants. But I'm not going to give him a two year supply from
his two week membership.

Also as Shap mentioned, some of the members with high speed connections want
fast downloads. Often, half of the available server speed is taken up by the two
guys ripping the site. They are each using 16 connections, squeezing out 30 legit
members who are trying to download a video to watch. If those two guys have FIOS
they can easily load down the server to where it's hardly usable. By controlling those
two members, the site will be faster for all of the other members and retention goes up.

So for me, those are the three more important points - reducing the spread of my
content on peer to peer networks and such from people ripping, in order to
increase sales, retaining members by encouraging them to keep their membership
going rather than doing a drive by "download all you can and leave", and keeping
the site responsive for the vast majority of members. those points are more
important, probably, than raw bandwidth cost.

Even bandwidth cost shouldn't be ignored by many sites, though. The bandwidth
cost to support a legit member is cheap, no problem there. We're not talking about
legit members, though. The bandwidth cost of constant ripping can easily double
may overall costs, though, and that along with the other three reasons to keep
it under control shouldn't be ignored.

Simplistic controls that have been used in the past can certainly have drawbacks,
though, which I think has given the whole idea a bad rap. For years our own web
site had an explanation of why bandwidth limits, as commonly used, were probably
not a good idea. Maybe a guy is really horny today and wants to have three "sessions"
on your site today. That's actually OK, as long as he doesn't download a shitload
EVERY day. So you really need to look past just "today". Throttlebox extrapolates
usage out over an infinitely long period of time, so it's considering all activity the user
has ever had to decide if he's generally abusive or not. Along with looking long term,
you also want to control the ripper using 16 connections to download a shitload
right now, slowing the server. You don't want to let him hammer the server for six
hours before you tell him to chill for a while. So to really be smart about it you look
at both the very short term and the long term. There are other ways to be smart too,
of course. Fifty minutes of video is about 500 MB. 5,000 pictures is also about 500 MB.
One is clearly reasonable usage, the other clearly is not, though they are both 500 MB.
Throttlebox can tell the difference. Throttlebox would allow 500 MB if it's fifty minutes
of video, but would not allow 500 MB that consists of 5,000 pictures.

So in summary, I think there are four very good reasons to control this kind of
abuse, four reasons which all help increase retention, but you have to be smart
about it - or rather, you need a system which is smart about it.