Oracle and MySQL are still the most popular DBMS in the market according to many sources, e.g. this one here: http://db-engines.com/en/ranking http://db-engine

Oracle and MySQL are still the most popular DBMS in the market according to many sources, e.g. this one here: http://db-engines.com/en/ranking http://db-engines.com/en/ranking Also, note that MySQL was the only half-way trustworthy free database in the market. The popularity of PostgreSQL has been on the rise only since a few years. So if "free" (as in beer) is what you're after, then MySQL was the only choice for a very long time. Once you build upon MySQL (or any DBMS), you don't switch easily... Given that RebelLabs is not mainly focused on JRebel users (it's more of a general ZeroTurnaround content marketing platform), the target audience is certainly JRebel-friendly. So yes, the results are biased towards that sort of audience.