When it comes to web hosting documentation, DreamHost must be one of the best. 11 years in the hosting industry has resulted in an established wiki library of technical articles about LAMP hosting, specially tailored for the DreamHost users.
Almost all possible problems and common web hosting questions have been addressed in this library. Be it about their proprietary control panel, or the best security practices of PHP, or the performance tuning of MySQL, or the usage of .htaccess file, or the tutorials of 3rd software such as WordPress, you can find plenty of helpful articles well written there.