NZB Files Made Simple
An NZB file lists content that Usenet software can download.
NZB files are a list of posts that you want to download from Usenet. Most often, they list all of the parts of a single piece of content that you want to download. It doesn't sound as powerful as it is, but imagine that you have found a 4 Gigabyte video on a news group. If it was uploaded in 1 Megabyte blocks then it is in 4,000 pieces! If you are browsing a newsgroup, then your Usenet software will just combine all of these and show you 1 listing for the single item that it really is, but what if you wanted to tell someone else about that 4 Gigabyte video? Better yet, what if you wanted to use a search engine like NZBindex.nl to find things that you like and have your software download them? That search engine needs to be able to give you something to help your software find the 4,000 pieces of that video. That something is an NZB.
So, your friend sent you an NZB file for a great post, or you found something on a website or search engine that looks interesting and you got it from them. It's a thin little thing that looks almost readable if you opened it (go ahead, it's ok).
It has all of the information for each segment of the content, in an XML-based format. This includes the newsgroup it was posted to, the subject, who posted it, the date, Message-ID's, and the size of all of the parts.
Now you need software to be able to actually use it to download. The most popular software currently out there for this is SABnzbd. It has a massive user base and is stable, fast, free, works well with indexers, and it's also open source.
Once you have SABnzbd installed, you can give it this one little NZB file and it will get everything automatically, even taking care of any decompression or repair if it is needed. This can be done by just double-clicking on the NZB and or you can give it the URL so you don't even need to have it on your computer, this just depends on what is easier for you.
That's it, they are pretty simple. They provide an easy way to tell other people about large files. They aren't the files themselves, but a condensed list of them that your software can use to get the actual content. Once you give the NZB file to your software, the process is totally hands off and as automatic as if you had double-clicked on something to download from a newsgroup.
As you can see, they make web-based Usenet search engines and indexers possible, and can make your downloads and sharing your finds with friends much easier.
Usenet indexers are search engines by another name.
An indexer scans the content of all newsgroups and organizes the data to help you make logical sense of the vast amounts of content in the groups. This is a big accomplishment as Usenet currently consists of 43 Petabytes of data in 103 Billion posts, across over 100k newsgroups. As you would imagine, the server hardware required to do this is not insignificant and often requires multiple large dedicated servers.
Imagine trying to browse web pages and find something interesting without a search engine. That is the difference that an indexer makes for newsgroups. Instead of having to browse huge newsgroups by hand, they let you search specific groups, all of them at once, or restrict your search to a range of groups, file types, and sizes.
Some indexers stop there, and that is a wonderful help for most people, but there are indexers that go beyond indexing for searching. These indexers try to make sense of the files posted to news groups. They scan it for being obvious SPAM or a virus, then attempt to categorize the file by subject, sub-categorize by file type, and (if it is a video) even determine the video quality and length. Some even let you keep a list of what you want to download and notify you if it thinks something is posted that matches.
It is a lengthy subject, but don't get overwhelmed. Start with a good but simple "search and download" Usenet indexer. Just don't forget, you will still need something like Newsbin (which we provide for free) to actually download the files you find listed, because the indexer will give you NZB files that still need to be given to Usenet software.