Google's core algorithm update that took place in mid-April was officially approved four days after it actually took place.
According to Google, this is a broad update, so there is nothing specific webmasters can do besides "continuing to improve content quality." but on the other hand, Google did imply that these core algorithm updates could now benefit sites that were not rewarded properly in the past.
According to external tests that included large databases (such as that of G-Squared Interactive), there seems to be a close connection between this update and the “Brackets update” that occurred about a month ago.
For some sites the improvement or weakening in rankings has increased, while for others the trend has actually reversed.
If so, how can one explain that in some sites the trend had reversed even though they hardly changed their content? The explanation is that the site probably had other issues, for example:
• The main content required allot of scrolling and was not “Above the Fold”
• Excessive amount of ads or pop-ups
• Duplicate content (especially if it is buried at the bottom of the page, way “below the fold”)
Since the effect of this algorithm does is similar to the effects of the historical Panda content update, there is a theory that this is actually a Panda algorithm update, which is now embedded into Google's core algorithm.
What to do if your site has been damaged?
Similar to the March update, we recommend to improve content quality and to make sure the content is relevant to what the user is looking for (a well-written content does not necessarily mean the user is getting what he was looking for). Make sure your content is original. There’s no need to address minor changes you may have made between the two updates as they are probably not significant.
If you use aggressive tactics to increase conversion rates, such as using a large form which darkens the screen (in order to receive users email addresses), you may want to consider alternatives.