We wanted to have a quick clear button for any text field (similar to address bar of browsers in mobile and tablet devices). Snapshot below might explain it much better. In this you are seeing email search field in newsletter filter form.
In a Drupal site, if we have any module upgrade or configuration related work to be done in our live site, it is recommended to put the site in maintenance mode, so we can prevent end users from experiencing glitches.
Contextual link is a nice addition made into Drupal 7 to favor usability. It offers, quick links to pages performing administrative operations. By default it is available for core block and node teaser view.
At KnackForge we use Drush more often as a part of Drupal development projects. As Drupal developers, we frequently feel the need for getting the most recent database dump from live site.