Major Fashion Houses
The peaks all correspond with the month of December. The dashed lines here mean that each search is within a certain topic (the grey description beneath each company name is the topic). This means that searches related to the company Prada are included, while searches for the movie "The Devil Wears Prada" are not. The category for all searches is "shopping", which includes everything from apparel to consumer electronics.

Interestingly when the category is narrowed to "luxury goods", the results are much different. Perhaps this is due to diffusion lines? The end of this seems to confirm this guess.
Sometimes an increase in searches is simply due to an overall increase of searches within that category. When "Compare to category" is checked, we can see the relative increase of searches compared to the increase of searches related to that category (in this case "shopping"). Looks like Chanel has had the largest increase in searches compared to the increase in general shopping searches.