As fantastic as NZB files are, they are not without flaws.
Flaw #1 – NZB Files Can Go Stale
When choosing an NZB file on an NZB indexing site, you should try to select one that was created recently. Your Usenet server may not store files for as long as your NZB site stores pointers to them. There is no way for the NZB site to know if the NZB file has gone stale. They would have to monitor every Usenet server in the world, constantly checking to see if the files were still present, and that isn’t practical.
This is quite a large flaw since many NZB newbies probably download oldish NZB files without noticing, and try to use them with the lousy newsgroup server that comes free with their internet account. After a few tries, they may conclude that the entire NZB concept is flawed.
Flaw #2 – Human Error Can Cause You to Miss Files
The NZB files you find on curated NZB indexing sites are created by human editors who manually examine Usenet newsgroups and create NZBs for the files they find there. These editors are usually volunteers, and not only are they prone to human error like anyone else, they often don’t keep current with the newsgroups they have assumed responsibility for. In some cases, no NZB files will appear until days after the files were posted.
If you want files as fast as possible, and to be guaranteed never to miss anything, you must access the newsgroups directly. You can use a program like The unPoster, which will list every file as soon as it appears, or NewzScape, which will simply download every file it finds as soon as it appears. See the newsgroup software page for a rundown of the various ways to access newsgroups directly. A good balance is to use NZB files for non-critical items, and a newsgroup program for the items most important to you.
Flaw #3 – Legal Issues Can Cause You to Miss Files
Suppose that an NZB site is required to take down an NZB file because it violates a law in the jurisdiction where the site is located. If you live in a different jurisdiction where the file is legal, then you may still be able to download the file by downloading directly from the newsgroup.
An example of this situation might be if you are Chinese and living outside of China. You hear about a certain politically sensitive file, and go to a Chinese NZB site to look for it. However, the Chinese government has got there first and forced the site to remove the file. But since Usenet is global, the actual file has propagated to hundreds of news servers around the world, and is probably sitting right there on your own ISP’s server.
It is possible that the Chinese government could file complaints with ISP’s around the world and get them all to take down the file, but that takes time. It also can only be done after the fact. So, if you are using a program like NewzScape to simply download everything as soon as it arrives on your Usenet server, then you are very unlikely to ever miss anything.