DMCA is a US specific copyright law. In this act any content spread across the web on united states properties will be taken down under this act. So for example if any piracy site spreads the new released movies or copyrighted content from another website, then in such cases the DMCA can be used to take down such sites. Also the DMCA act can be used to take down the content from most of the websites online. Though DMCA is country specific law for US. However many non US companies are also using the DMCA declaration to take down the content to avoid legal issues.
The reason being DMCA is treated very high risk for any online piracy or any such site. Those people end up in legal take-down notices and if the company is protected under US laws then they may lose advertiser accounts from adsense, amazon etc. So DMCA is very strict notice and being taken seriously all over the web.
If you wish to file it, there are some of the sample templates online that may suit your case, download, fill it up and send it to the respective parties.