I think you may have some interesting information to add, but your comment currently reads like aped talking points, with a dash of accusing someone asking a reasonable question of trolling.
Most people simply don't understand MySQL. MySQL is unique in as it support many database engines [4], it's like a common SQL layer on top of dozens of database engines. MySQL had a bad reputation because of its old MyISAM engine [2], the former default engine (one of many). The current default database engine is InnoDB [3] which is very fast and is what Facebook and many other huge web sites use.
Instead of repeating myself and others, MySQL+memcached is quite popular, check out the highscalability website [5].
[1] http://en.wikipedia.org/wiki/PostgreSQL , http://stackoverflow.com/questions/12622524/postgresql-9-2-1... , http://stackoverflow.com/questions/110927/would-you-recommen... , etc.
[2] http://en.wikipedia.org/wiki/MyISAM
[3] http://en.wikipedia.org/wiki/InnoDB
[4] http://en.wikipedia.org/wiki/Comparison_of_MySQL_database_en...
[5] https://www.google.com/?gws_rd=ssl#q=site:highscalability.co...