Computer crimes, though they take place in a "virtual world" of bits and bytes, have a widely felt economic impact, estimated by some, to be in the range of US $500,000,000 per year. Widely publicized computer crimes have included:

• identity theft
• changing one's personal finances or scholastic record by computer fraud
• hacking and other unauthorized use of computer equipment
• viruses and trojan horses and other computer vandalism or misuse
• child pornography

Additionally, there are many other ways in which computers intersect with crime:

• research done on the Internet in connection with physical crimes
• as an aid in counterfeiting
• crimes of false origin, such as emails with bogus "From:" addresses, or newsgroup postings designed to harm the reputation of someone other than the true author

Additionally, computers can hold evidence pertaining to the state of mind of criminals, pertaining to the desire (often thwarted by computer forensics) to delete data, and pertaining to planned events. Computers and hard drives are rich sources of information for investigators, and as such it is important that the evidence be collected properly by an independent forensic company.