It really states which chars aren't allowed. The square brackets are required. The following string represents one word in the typical username. Basically, a word is either an atom or quoted string. Wireless technology is increasingly being used by companies to track customers' product inventories.
Analysts say the use of mobile technology in supply chain applications is only now gaining steam.
Count Aircraft parts distributor Aviall, Nicor Gas and office supplies provider Hunt among those using utilizing the technology.