Essay: www.sxe.net — Community, Controversy, and the Evolution of Early Internet Subcultures
Malware: Sites hosting cracks and keygens are primary vectors for trojans, spyware, and ransomware. Even if the file you want is legitimate, the pop-ups or "download buttons" on the site often lead to malicious advertisements.
Abandonment: Because the site appears to be unmaintained, it is vulnerable to exploitation. Hackers often inject malicious scripts into abandoned domains.
Legal Issues: Downloading cracked software is illegal and violates copyright laws in most jurisdictions.
Display auto-generated ads (some of which may be malicious).
Be redirected to suspicious or phishing sites.
Attempt to download unwanted software.
Pornographic redirects.
"Link farms" that host malware.
Browser hijackers (changing your homepage/search engine).