Just incase any of you haven’t heard, AVSIM was recently taken down by hackers, which in effect destroyed their complete forum, and downloads databases. These guys have been running for 13 years now.
What evidence do you have that PHP is not secure? PHP and .NET are as secure as you make them. You can punch holes in any language, depending on how bad of a coder you are. PHP is not any more or less secure than .NET.
Their site was not hacked because of their coding; someone physically was at the command line and striped the partitions from the drives.