Drupal core hacks - thinking about it?

Funny results from searching Google for ‘drupal core hack’:

Do not hack core | drupal.org
29 Jan 2009 … “Do not hack core!” This phrase is commonly heard in the Drupal community. There are even t-shirts made with this phrase and this cannot be …
drupal.org/node/144376 - 16k - Cached - Similar pages

Documentation: Info on Core Hack [...]

Drupal performance tuning

This won’t be the last post about Drupal performance tuning I guess.
Some steps you can follow to increase the performance of your Drupal-based website (if you need so), in no particular order:
Don’t let the database handle the cache

Add memcache support (no surprise there): Install memcached on your server (or on a few of them). On [...]