You can easily code in a metatag to display on certain domain only when use domain access module. Valid example for this is when you have a multiple domain installed on the same directory and utilizing domain modules to switch between different domain, and you don't want Google or any search engine robot to crawl some domain.
You may argue that this can be done via robot.txt, and for multiple domain some fancy .htaccess rule with redirection to different robot.txt files for each of the domains respectively. The answer is yes, you can achieve the same results with this way too.
After neglecting one of my websites for a couple month, I decided to do some maintaining and logged in to the site as admin. To my surprise, eventhough the site is "Protected" by mollom as spam protector, I got 132.149 unapproved SPAM comments.
Sometimes when building an advanced Drupal form that involves form_alter plus including files you will encounters problems that Drupal is complaining about a missing functions that is in your include file.
This problem usualy happen if your form submit function utilizes $form_state['rebuild'] = TRUE or invoked via ajax. Drupal form system is smart enough to auto load all of your include files if you call it using module_load_include() function, or form_load_include() function.
Drupal 7 is getting mature as the time of this writting and many of its contribution modules is on stable state.
Here is a list of top 20 Drupal 7 modules that you must install to enhances your Drupal Site
This module will provide you with tokenized feature. Most important for automatic pathauto pattern.
Without this Drupal can still provide clean urls but without any automatic pattern generation
If you are a savvy drupal coder then you should know that it is very tricky business to create a table output with sortable header and forms in the row.
Why? is this hard to do in Drupal 6?, the answer is most example on the internet will point to do a "sortable header" in a table via theme layer, while to include a "form element" we need to utilize a form array that called from drupal_get_form() function.