Deus ex Machina
Crack tracker requests removal of pirated software, ebooks, games, music and video dowloads on grounds of copyright infringement. Whoever uploaded your cracked software to some file-hosting website is morally reprehensible as a pirate, but can be technically dealt with as a violator of your copyright, under the provisions of DMCA (Digital Millennium Copyright Act).
Accusing someone of copyright infringement is a serious allegation, and normally you would need a lawyer to write a formal letter of complaint. Thankfully for the software author (or artist, writer, etc) internet piracy is so widely spread that file-hosting sites like fileserve.com, filesonic.com and the hundreds of others like them, cut through the red tape and accept simple requests for removal of illegal downloads through a simple email.
Crack tracker automatically sends emails for all the illegal download URLs it finds for you, asking the file-hosting website to remove them. The DMCA takedown notice is served through a simple email, which can be just a polite request to remove a list of downloads without any jargon. Crack tracker's default email template has a bit of legalese in it, so that it sounds a bit more menacing ("I hereby certify under penalty of perjury..."). It also pays to add your company contact details and a telephone number, making your email look more formal. Most of the time this is all it takes to remove your software from download websites.
There are however some websites like letitbit.net (and a few others controlled by the same group) that need more convincing. If you just send them a takedown notice via email, they will write back asking for a letter in PDF format attached to an email, with more or less the same information. I don't know why they are so fussy, perhaps they take copyright infringement allegations too seriously—or they simply want to make the life of software ISVs harder and discourage further takedown notices.
But that won't stop the determined copyright owner. All you have to do is find the email Crack tracker sent for you (e.g. from MS Outlook Sent items folder) and turn it into PDF format. On windows you create PDFs through a virtual printer driver — I use the free doPDF. Simply 'print' the email selecting the doPDF 'printer' and a PDF file will be saved, which can then be attached to the original email and resent to the website's abuse department. If you want to be even more convincing you can create a real letter like the one to the right, using your company logo etc. I have a MS Word template letter and paste the URLs Crack tracker finds.