When Google rolled out Panda 4.2 they told me this will roll out over months and months, a very slow roll out. It was just technically how this roll out was happening they told me.

John Mueller in a Google+ Hangout added more things on record about why it is rolling out slowly. Well, why is still not answered but he did add some more advice around the slow roll out.

In summary he said:

The roll out is similar to previous roll outs
This one is slower because of “technical reasons”
John actually said there is “an internal issue” for the technical reason but I am not sure he actually meant that.
This is not rolling out slowly to confuse webmasters

He mentioned it in three different points in the hangout, let’s go through each:

At the 25:30 mark the question was:

John answered:

At the 37:14 mark the question asked was:

And then later on, at 39:50 mark John added:

Take what you want from these clarification points. It still doesn’t answer all the questions webmasters and SEOs have on the slow Panda 4.2 roll out.

Forum discussion at Google+.