have a look at this very interesting article on wired online talking and compairing Beagleboard to the Arduino success:
For electronics hobbyists, the open source chipset BeagleBoard that packs as much punch as a smartphone processor might seem like the key to paradise.
Yet it is the relatively underpowered 8-bit microcontroller Arduino that has captured the attention of DIYers.
Arduino began as a project in Italy in 2005 and since then has turned into an open source hardware movement. There are thousands of Arduino projects today such as electric meters, guitar amplifiers and Arduino-based gadgets that can tell you when your plants need water.
The Arduino community is at least 100,000 users strong. But it is not alone.
Other open source projects like the BeagleBoard, which is shepherded by Texas Instruments, are trying to win Arduino fans over.