Laws of the electronic land
Law #1: If a bad guy can persuade you to run his program on your computer, it's not your computer anymore.
Law #2: If a bad guy can alter the operating system on your computer, it's not your computer anymore.
Law #3: If a bad guy has unrestricted physical access to your computer, it's not your computer anymore.
aw #4: If you allow a bad guy to upload programs to your Web site, it's not your Web site any more.
Law #5: Weak [OR BLANK!!] passwords trump strong security.
Law #6: A computer is only as secure as the administrator is trustworthy.
Law #7: Encrypted data is only as secure as the decryption key.
Law #8: An out of date virus scanner is only marginally better than no virus scanner at all.
Law #9: Absolute anonymity isn't practical, in real life or on the Web.
Law #10: Technology is not a panacea.
Borrowed from TechRepublic.