I'm not sure what you're referring to as "the post". If you're referring to the article, my comment wasn't addressing that at all. My comment was a response only to mikeash's comment. He gave an incomplete description of trademark erosion and I thought it was worth clarifying. Using "IMAX" to refer to a non-IMAX screen would be trademark erosion. Using "IMAX" by itself to refer to an IMAX screen is still trademark erosion. Just as "googling" is an erosion of the Google trademark, even when referring to Google's searching service.
You see the impact of this sort of brand erosion with the iPad. The iPad dominates the tablet space, so the constant references to iPads have started to genericize the term to the point that other tablets are often called iPads (which erodes the brand to a greater extent). Contrarily, BMW for example gets away with this because BMWs do not dominate the market, so there is little danger of "BMW" becoming synonymous with the car. IMAX dominates its market so the brand is quite in danger of becoming a synonym for a giant screen. The smaller erosions are therefore a bigger concern.
You see the impact of this sort of brand erosion with the iPad. The iPad dominates the tablet space, so the constant references to iPads have started to genericize the term to the point that other tablets are often called iPads (which erodes the brand to a greater extent). Contrarily, BMW for example gets away with this because BMWs do not dominate the market, so there is little danger of "BMW" becoming synonymous with the car. IMAX dominates its market so the brand is quite in danger of becoming a synonym for a giant screen. The smaller erosions are therefore a bigger concern.