Scent is an important sense; things just taste better when they smell good as well. With that in mind, the Aroma coffee lid claims to improve the taste of coffee by enhancing its smell.
The lids have "an aromatic material formulated to enhance the bouquet of the coffee" built right in, one that will make your coffee smell more like coffee and therefore taste better. The company behind the lids, Mint Urban Technologies, is hoping to get the lids to places like Starbucks to improve the flavor of their brews.
Of course, simply popping the lid off would presumably do an even better job, but you can't make any money telling people to drink coffee without the lids on their cups, can you?