Torrent facility is most widely used to download music albums, movies and softwares from internet. Torrent clients take care of getting chunks of data from its peer computers and put them together to realize the complete data. But there are some hidden vulnerabilities if you use to download data using torrent facility.
Major threat will come in to picture when you download softwares with cracks and keygens using torrent facility. Most of the time the pirated softwares with cracks and keygens will have trojens, adwares, malwares bundled along with. So you are compromising your own computer security for saving few bucks needed to buy original softwares. So never download any keygen or cracks using torrent facility. And never ever download any antivirus software using torrent, as the software itself might be infected with viruses.
Another threat is from sites which provide torrent info files, which are required by the torrent clients to download compete data. Some sites may tend to download some adware or trojans to your computer automatically. So its always better to browse with SiteAdvisor extension installed.
Also install antivirus software for protecting your computer against latest threats. See the best antivirus reviews and comparisons for choosing your antivirus software.