I can't comment on the actual article, so here are my points:
-this shows a case of substitute goods that happen to be merit goods. the manufacturer, Philips, has created an eco-friendly lightbulb that will last about 20 years. however, it also has other eco-friendly light bulbs that cost a fraction of the current set price.
-the price is currently quite expensive, but the manufacturer is currently subsidizing the product for customers.
-a diagram of positive consumption externalities can be shown, using the prices mentioned in the article.