Story Developing - Follow me on Twitter @chadgingrich for updates.
Today we started seeing across many clients that video snippets stopped appearing in the SERPs for domains. YouTube snippets are unaffected, however, it seems that video snippets may be going the way of authorship thumbnails. No official word from Google yet, however, the change seems to be pretty widespread with snippets seemingly disappearing from Moz (WBF) and the Wistia blog. It's a lot of speculation at this point and the SEER team is currently crowdsourcing examples that would disprove a total removal. At this point we are still seeing a number of high authority sites still displaying video snippets in certain cases (more below). It also appears that the snippets are still showing in Video search, however, not when searching in Web SERPS.
You can also use a site search operator to display all of the pages that should be displaying video snippets to check your domains. See below where we compare Vevo's video pages (which are still getting snippets) to Moz's Whiteboard Friday posts (which have lost snippets).
We are spot checking queries, including a few with the negative site operator for Youtube.com (which will weed out any YouTube results). We're starting to put together a list of currently affected queries along with any queries that are still showing thumbnails - please add any additional you find in the comments below.
Still Showing Snippets
query: louis ck highlights (screen.yahoo.com & cc.com) query: how to fry an egg video (allrecipes.com) query: chocolate chip cookie video recipe -site:youtube.com (a number of sites showing here) query: time lapse video (video.nationalgeographic.com) query: teach me how to dougie -site:youtube.com (mtv.com) query: marcel the shell (vimeo) query: knit a blanket video -site:youtube.com (dailymotion) query: beyonce single ladies (vevo, dailymotion) query: kanye west gold digger (vevo, vimeo) query: how to groom your dog -site:youtube.com (monkeysee.com) query: edicisum (vimeo) query: cooking video tutorial (goodhousekeeping.com & divascancook.com) query: cooking video tutorial (joyofbaking & nytimes.com) query: how to cut a mango -site:www.youtube.com (allrecipes, simplyrecipes.com) query: breaking bad best clips -youtube.com (imdb.com) query: lost best clips -youtube.com (Fox News)
No Snippets
query: excel tutorial -site:www.youtube.com query: auto repair tutorial -site:www.youtube.com query: iphone repair tutorial -site:www.youtube.com query: mad men video recap -site:www.youtube.com query: game of thrones video recap -site:www.youtube.com query: repair a water heater video tutorial -site:www.youtube.com query: repair a flat tire video tutorial -site:www.youtube.com query: game walkthrough -site:youtube.com query: how to cut a watermelon -site:www.youtube.com
Some further evidence can be seen using the SEMRush "SERP Source" screen shot. If you take a look at the query "iphone 5 review video" the results on SEMRush's snapshot from July 11, 2014 are vastly different than the current results. On July 11th in the top 20 results, 10 videos from 10 different domains were receiving video snippets (including 1 YouTube result). Currently on July 16th in the top 20 results, only 5 videos from 3 different domains are receiving video snippets (2 YouTube, 2 from The Guardian, and 1 from NDTV.com).
- A compete removal of all snippets for any sites except for YouTube.com and it's rolling out slowly similar to authorship thumbnail removals.
- A change in Google's requirements to actually display snippets similar to their mass reduction of review star ratings last December. Right now the example queries above that are still showing snippets tend to be of higher authority AND/OR have the word "video" included in the query.
- It could simply be an index refresh (re: @PhilNottingham)
- It might be a change regarding how prominently a video is displayed on the page (re: @Wistia)
We'll keep this story updated as we learn more.
UPDATE 7.17.14 7:00am PST: Mozcast data from yesterday confirms the significant dip in video snippets. 
Yoast chimes in, seeing it as well with Dr. Pete's analysis pending. Still no word from Google but stay tuned for updates.
UPDATE 7.17.14 11:30am PST: Wistia has put together some additional research that you can read in full here. They provide a great breakdown of a few theories that could shed some light on what we can expect from this change. Additionally, they report that they aren't seeing many rankings drops from the removal of the snippet which could mean this is a purely cosmetic change to the SERPs. They have an open call for data so reach out on their post and share what you're seeing.
SEOlytics has also chimed in with a great sampled data test and breakdown. Their analysis of 10,000 video results shows that changes are still happening (through today). They also have a percentage breakdown of domains that are still receiving thumbnails.
Image Source: SEOlytics
UPDATE 7.17.14 2:25 PM PST: @dr_pete confirms Mozcast data
UPDATE 7.18.14 1:04 PM PST: John Mueller seems to refute an overall removal and says that seeing changes is normal from time to time.
UPDATE 7.18.14 2:12 PM PST: Jennifer Slegg from The SEM Post has released an article with some more research from the past day illustrating additional changes. It seems SERP rankings are more volatile right now as well. She was also able to obtain a quote from a Google spokesperson stating, "We'll continue to show video snippets where it's most relevant." Which you can interpret a little differently than Mueller's quote. It could reflect that what Google deems as "most relevant" for a video snippet has become much narrower.
UPDATE 7.21.14: John Mueller confirms that snippets aren't going away but that Google has started to limit when (and how many) they are shown. It's unclear at this point what Google's new requirements are.
