that's a pretty poor methodology description... what constitutes a brand mention? just the brand, any tag with the brand name in it? any product mention associated with the brand? which acronyms were included?
i would assume MS being focused more on a product would include more MS-based tags where with Sony and Nintendo showing more focus on games their tagging would mostly include just games... e.g. it'd be redundant for most Super Mario tags to also include Nintendo; at best games like GOW would probably include a tag such as PS4, not Sony.
MS had the best brand showing IMO so I'd wager they still received more mentions. but I mean, really, that methodology is not very clear... is there a different section somewhere? or is it 'proprietary' hhh