When Google announced the mobile first indexing change, and revealed that they are now beginning to test it, many site owners began over analyzing their stats to see if they could see any changes with Googlebot crawl activity or search referrals from Google.
Some thought they are see a lot of desktop crawl throttling, but that is unrelated, according to Paul Haahr. And normally an increase or drop in crawl rate isn’t a sign of a manual action or algorithmic issue impacting the site.
.@BritneyMuller I would be very surprised to detect any effects of mobile-first indexing at this stage (cc @BermanHale)
— Paul Haahr (@haahr) November 6, 2016
Of course, if a site has a large enough data set, they may be able to notice minor changes that could possibly be attributed to mobile first.
Google first revealed the move to mobile first last month, but released many more details on Friday. You can find all the important information on mobile first indexing in our guide.