For much of the last decade the use of column based approaches has been very much a niche activity. However, with a substantial number of vendors now active in the market, with over 2,000 customers (many of them Global 2000 companies) between them, we believe that it is time for columns to step out of the shadows to become a major force in the data warehouse and associated markets. Given that view, this paper will define what column-based relational databases do and how they do it, and where they have advantages (and disadvantages) compared to traditional approaches. This, in turn, will lead to a discussion of the sort of environments for which columns are best suited. Up to this point all discussions in this paper are generic. However, we will conclude with a section on Infobright, a column-based vendor, discussing how its technology has extended the column-based paradigm to provide additional performance and other benefits.