The name of this place is somewhat misleading. It's likely that this 'coffee house' sold more wine than coffee, since coffee was only just becoming popular. I know it's hard to imagine a time when people didn't enjoy their morning cup, but there you are.
If we go by the number of bottles they had in stock, this was one of the busiest taverns in Boston - likely because of its location. If you were arriving in Boston by ship in the 1700s - and let's face it, you didn't fly in- this would have been the first tavern you saw, and since taverns were great places to get information, you might well have stopped here for a drink and the latest news.