I've not had much of a chance to use it yet, but flicking through I found this, which I found very interesting.
"Ethical consumerism is just as much about supporting the 'good' companies and products as it is withdrawing our support from the 'bad' ones."
"Positive Buying
This means favouring particular ethical products, such as energy saving lightbulbs.
Negative PurchasingThis means avoiding products that you disapprove of, such as battery eggs or gas-guzzling cars.
Company-Based Purchasing
This means targeting a business as a whole and avoiding all the products made by one company. For example, the Nestle boycott has targeted all its brands and subsidiaries in a bid to get the company to change the way it markets its baby milk formula across the world.
Fully-Screened Approach
This means looking both at companies and at products and evaluating which product is the most ethical overall."