From Seo Wiki - Search Engine Optimization and Programming Languages
ID-Ten-T Error (also seen as ID10T and ID107) is a term often used by tech support operators and computer experts to describe a user error, a problem that is attributed to the user's ignorance instead of a software or hardware malfunction. It is a masked jab at the user: when ID-Ten-T is spelled out it becomes ID10T ("idiot"). It is also known as a "Ten-T error" or "ID:10T error".
A highly popularized example of this is a user mistaking their CD-ROM tray for a cupholder, or a user looking for the "any key". However, any variety of stupidity or ignorance induced problems can be described as ID10T errors.
In Navy and Army slang, the term has a similar meaning to that describable above though it's pronounced differently:
- The Navy pronounces ID10T as "Eye Dee Ten Tango". 
- The Army pronounces 1D10T as "One Delta Ten Tango". 
- 1D10T (pronounced "one dee ten tee") is also used in Army slang in reference to the massive amounts of paperwork involved in getting anything done, e.g., "this requires a one dee ten tee form".