Correct me if I'm wrong, but to use the !bang system you have to memorize the short form for every site or service you want to use it for, is that right?

For example, amazon.co.uk is !amazonuk - I don't see the meaningful improvement there.

DDG has six thousand of them, most of which don't benefit from a great shortening of the name. To search answers.com it's !answers - that's an extremely small improvement over site:answers.com given the need to memorize a bang for each thing you want to use it against.