Marketing...
It's not really a lie: you will get high speeds (if you know how to configure LW and what/how to download) but the most you will ever get is a little less than what your bandwidth (as your ISP advertises it) says.
Again, there is only one way to get faster speeds than what you pay for: pay for more...

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iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-