NZBFinder is a usenet indexer and searcher. This means that you can use the website and/or API to search things you want to download on usenet.
Usenet is a popular old skool way to download TVSeries and Software. Since it was too easy to download illegal stuff here companies had several lawsuits to make it impossible to do. So far they did not succeed completely, but they did make it more difficult to download. Most items on usenet are not anymore easy to understand and searchable because the names have been garbled. They do this to make it last longer available. To really search these days, you need a usenet indexer on top of it. like NZBFinder is. This website makes usenet searchable again for your movie, tvseries or software download.