Google monthly updates for May has been less 39 when compared to the previous month April 50 updates
Well I would always look into the items, which are closely related to one, other like Inorganic Backlinks & Penguin Improvements
Below mentioned snippets shared from Google.
Better application of inorganic backlinks signals. [Launch codename "improv-fix", project codename "Page Quality"] We have algorithms in place designed to detect a variety of link schemes, a common spam technique. This change ensures we’re using those signals appropriately in the rest of our ranking.
Improvements to Penguin. [Launch codename "twref2", project codename "Page Quality"] This month we rolled out a couple minor tweaks to improve signals and refresh the data used by the penguin algorithm.
The Below mentioned changes are the main things which I preferably feel most importance for Integrated Digital Marketing Person. Here is the list of Google May Updates for 2012 of Search Industry