This is a very useful module. If you use webforms a lot you know that if you give a role access to view all submissions that it means they view submissions to all webforms. This module solves that problem by putting extra access level at each webform.
I only wish there was a version for Drupal 6.
Setting up one Solr server with two or more Drupal sites takes some additional configuration. If this is not done, all of the data for each site goes into the same index and when searching on one site, results are returned from both sites. If that's not the desired result (faceting won't currently work correctly), then it is necessary to set up a separate Solr core for each site. Each core is a totally independent search index.
Here's a good article to help understand the difference between apps and mobile websites.
If you are new to developing for Drupal 7 or upgrading from another version, the examples modules is a GREAT module for examples on how to develop for Drupal using the API. It gives you the basic of a lot of the common things you do when developing. Some examples included are theming (hook_theme), running cron job (hook_cron), forms (hook_form, hook_element_info), menu, node and so much more!!
DrupalCon Denver 2012
DrupalCon Denver is the official conference of the Drupal community and will be held in Denver, Colorado from the 19th-23rd of March, 2012.
I submitted a proposal titled Drupal Development is not just for Programmers... "There's a Module for that!". 565 sessions were submitted so the competition is tough.
This article on Newfangled.com does a good job on describing how your website design can determine how long your users will stay on your site.