Most likely it's a joke. USB doesn't have the bandwith or the power required for graphics. Get a regular PCI-E graphics update instead. If your current card is very old you can get substantial improvement from current 100 dollar range cards.
I would have done that already if I wasn't on a laptop.
Time of this report: 8/24/2010, 07:52:37
Machine name: TYLER-PC
Operating System: Windows 7 Home Premium 32-bit (6.1, Build 7600) (7600.win7_gdr.100618-1621)
Language: English (Regional Setting: English)
System Manufacturer: Hewlett-Packard
System Model: HP Pavilion dv7 Notebook PC
BIOS: Default System BIOS
Processor: Intel(R) Core(TM)2 Duo CPU P7450 @ 2.13GHz (2 CPUs), ~2.1GHz
Memory: 3072MB RAM
Available OS Memory: 3070MB RAM
Page File: 1441MB used, 4694MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: Using System DPI
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7600.16385 32bit Unicode
Card name: ATI Mobility Radeon HD 4650
Manufacturer: ATI Technologies Inc.
Chip type: ATI display adapter (0x9480)
DAC type: Internal DAC(400MHz)
Device Key: Enum\PCI\VEN_1002&DEV_9480&SUBSYS_3624103C&REV_00
Display Memory: 2297 MB
Dedicated Memory: 1019 MB
Shared Memory: 1278 MB
Current Mode: 1600 x 900 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: unknown
Monitor Id: LGD01DD
Native Mode: 1600 x 900(p) (60.080Hz)
Output Type: Internal
Driver Name: atiumdag.dll,atidxx32.dll,atidxx64,atiumdva.cap,atiumd64,atiumd6a,atitmm64
Driver File Version: 8.14.0010.0678 (English)
Driver Version: 8.632.1.2000
DDI Version: 10.1
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 8/18/2009 03:20:38, 3105280 bytes
WHQL Logo'd: n/a
WHQL Date Stamp: n/a
Device Identifier: {D7B71EE2-D7C0-11CF-2A71-2E16A1C2C535}
Vendor ID: 0x1002
Device ID: 0x9480
SubSys ID: 0x3624103C
Revision ID: 0x0000
Driver Strong Name: oem24.inf:ATI.Mfg.NTx86.6.0:ati2mtag_M9x:8.632.1.2000:pci\ven_1002&dev_9480
Rank Of Driver: 00E62001
Video Accel: ModeMPEG2_A ModeMPEG2_C