This topic refers to a specific product (a cable) from Future Technology Devices International (what a name) or FTDI for short.
The FTDI cables bring out USB 5V to Vcc irrespective of logic level. Another issue to note is that DTR (used for auto reset on Arduino) is not available (they have RTS and CTS brought out).
These cables (the real thing if you like) have been around for a long time, but they've been copied and modified by other companies to meet different requirements. It is somewhat confusing because the 6 pin connector is the same (and they often trade by the same or similar name), but pins to signal mapping is different.
Se, check before buying and make sure you order something that fit your requirements.