In all the anime forums i have browsed around, i have noticed a lot of repetition on this question: which one is easier on my bandwidth, streaming or downloading? Animea seems to be no exception to this question and, as always, the answers I've seen are far from decent. Therefore I've decided to write this post, in hope that it will help the people in need of answers, while letting the rest of us laze out, and just directing them to this link :)
1. Internet bandwidth
Let us agree that the Internet is no finite resource. After all, it doesn't really strain the service providers to do their jobs - their expenses are near constant, and whether they forward us x information, or some number y>x, it's the same for them. Never the less, in practice, the quantity of data we send and receive is often limited by them. *
First of all, we need define the word bandwidth. Bandwidth is a fancy term us computer scientists use to describe the amount of data sent and received by our computers. In short, it is a limit as to how much information we can send out and take in.
Bandwidth is taken by anything you do with your internet connection, whether it is done actively or passively. Every program you have connected to the internet constantly sends out information or receives it, in a manner you cannot directly perceive. For an example, let us say you have a chat client - say MSN messenger - open. Even if you do not use it at the moment, as long as it's turned on, it consumes bandwidth. The reason for this is something called a 'handler', or 'action listener' - it constantly has to connect to a remote computer (again, we computer scientists just need to have a complicated word: server) and check whether it was forwarded information or not. Another example of this behavior would be a P2P client, such as uTorrent or Vuze - even if you're not uploading or downloading anything, it still has to connect to some computer somewhere so it does function.
As i believe you know, downloaded files do not grow on trees - they're files placed on some computer whose location we need not know (CS terminology: 'hosted' on a 'FTP (file transfer protocol) server'). Any time you wish to use some file, you copy it down to your own computer and access it from there ('perform a local copy').
This does not only refer to anime, though. Since the internet is simply an overgrown network of computers, much like a local network you can set up yourselves, it doesn't actually provide 'multimedia' like video or music. Anything you do, you do locally- as long as you're able to copy down the files for what you need, that is. For an example, if you want to view a web page, say AnimeA, your computer creates a temporary copy of the web site somewhere on your hard drive (which you could probably access if you wanted do), and just opens that one for you. Whenever you click on a link, say the Random section of the forums, it downloads that one and displays it.
Now, when you want to download a video, what happens? Pretty much the same thing: you find a computer that has it and just copy it down via the network. Then you manipulate it locally (say, rename it, play it or burn it to DVD).
Now the final point we need hammer down is how sites like Youtube work. Does the local file principle apply to them, too?
Open up youtube and type in a video. Now play it, and wait for it to 'buffer'. Annoying, isn't it?
That occurs because of a very simple reason: your computer cannot play something which does not exist. And the video part you're trying to play doesn't. Streaming is yet another fancy word, which has a very simple meaning, really:
Copy a file locally ('download it') a portion at a time, and then play the copied portions while the rest of the file is transferred. (OK, it doesn't mean that exactly, but it's close enough for this purpose)
That is why your internet connection and the time you spend wait for a video to 'buffer': you're not yet done downloading the video section you're trying to play.
So which one is easier on your bandwidth? Streaming or downloading?
I'd say they're about the same thing. Streaming does download the video to your computer - it just deletes it when you stop playing it (kill the page you're streaming off of). Also, it does so for lower qualities of video. Therefore, it's a pretty ineffective way of saving up a few dozen megabytes for even more anime.
My advice? Download your videos, if you can. And if you don't, at least copy them after the streaming is done (hint: the 'temp' folder, hint), or just rip them off the site using keepvid.com or something. You'll spend the same bandwidth, get the same low quality, but at least you'll keep the video for future viewing.
(Note to the moderators: I probably messed up the section of the forums i placed the video in. Would you be so kind as to move it to it's proper place? :) )
* No, you do not have 'unlimited' bandwidth. Check the very, very tiny letters in the contract you (probably) signed for details.
Umm... I have a bone to pick about #1. You still have to have a lot of hard disk space. Hard disks are expensive, and they wear out. Besides, it takes a lot of electricity to power a computer that manages the hard disk that stores your anime. This planet is frankly facing an energy crisis - producing the electricity to power the Internet takes a toll on the environment. As a result, it's harder to produce the necessary electricity. Dams are being removed, other methods of electricity production are not commercially viable, so the supply of electricity is not constant. Because of availability of electricity, its prices fluctuate. Whoever owns the datacenter (ISPs) where your animes are hosted, they are the ones who shoulder the costs. Of course, per person, per episode, it seems negligible, but it all adds up.
Even if electricity gets taken care of, hard disk space is still scarce. There has been flooding in Thailand this past winter, so hard disk factories are offline. ISP's have a responsibility of making sure that Internet is available to anyone who pays for access. And that means deciding to limit high-bandwidth applications like GPS and bittorrent, so that everyone, even people who don't use such applications have a reasonable level of service.
So no, an ISP's costs are not constant at all. They have reasons to do what they do. Customers who download animes are just a small subset of Internet users, even if they account for a disproportionate amount of bandwidth usage.
* baki has claimed Baki Hanma from Grappler Baki. Sig coming later. *
If you are worried about bandwidth I think it's better to look at streamed version of your favorite anime (if you don't intend to re-watch it later). Web versions of the anime are compressed and much smaller then the downloaded ones, also have a lower quality then the downloaded ones.
If you know you will watch a certain anime multiple times then downloading it is much better since it also has a better quality then the streamed version and it's practically free to watch it again.