ARDUINO as a USB datalogger?

Can the ARDUINO be configured to read text data being sent to a USB port off a device. I have a device that sends a text log to a flashdrive, but Id like to be able to have the arduino plugged in , rather than the Flashdrive, and then have the arduino feed the text file out to my computer.
Not sure where to start with the USB configuring. Been reading all about the complexe USB protocol, and Host/Client configs, and I think Im confused. Any info would help

I think so, for an Arduino that is capable of being a USB device such as the Leonardo or Micro. Since the USB interface of the chip will be connected to the 'device that writes a log file' you will probably need an external USB-to-Serial adapter to allow the PC to receive text from the Arduino.

Someone has probably already figured out how to make a Leonardo act as a "USB Block Device" (like a USB disk drive or thumb drive).

This project will do what you want: Four Walled Cubicle - LUFA (Formerly MyUSB)

But note - it is not part of the Arduino world. You will need to use the atmel tools directly