> They did so because in the late 1990s it was not possible to run multiple mod_perl applications on a single Apache process, but mod_php could do so.
When it comes to single factors explaining its success in the 1990s, the one I've heard cited more often is that you could embed PHP into HTML documents with the <?php ...> kind of deal, and a lot of shared hosts enabled that by default, making it by far the easiest way to get server-side scripting up and running.
Yep, trivial deployment model and trivial stack integration so every free host or ISP providing 20MB "web hosting" to users could give out PHP execution as well.
When it comes to single factors explaining its success in the 1990s, the one I've heard cited more often is that you could embed PHP into HTML documents with the <?php ...> kind of deal, and a lot of shared hosts enabled that by default, making it by far the easiest way to get server-side scripting up and running.