We've discussed most of these sites before on DonationCoder. You might be thinking to yourself "I already have an antivirus tool installed -- why do I need a slow online version?".
The answer is simple: These online sites will scan a submitted file using a large number of different commercial antivirus engines. This is exactly what you want to do if you need to figure out if a virus alarm is real or just a false positive overreaction by your specific antivirus tool. This happens quite frequently, and is especially important if you are a software author. These tools are the best way to find out if there is a consensus among antivirus engines about a file.
I will compare the number of antivirus engines used to scan an uploaded file, time taken to upload and scan, extra file upload methods, file information, upload progress meter and report page. I will also test the accuracy of the antivirus engines by scanning it with a detected version of Bifrost trojan.