There's been a seismic shift in the landscape of online reviews that those involved in promoting local business should keep an eye on.

The most significant change in online reviews took place in July 2011 with Google's removal of the review snippets from third party websites on Google Place pages and in the Search Engine Results Pages. These were once very prominent and then disappeared overnight.

This was not entirely unexpected since Google's relationship with several highly influential review sites has been repeatedly strained and downright hostile at times. Yelp and Trip Advisor both did some angry fist shaking at Google for taking their rich review content out of context and using it for its own purposes. It was obvious that something would have to change and it did.

The development that made this change viable for Google was its acquisition of its own critical mass of new reviews and ratings, gained first through its stand-alone Hotpot review engine and then through Hotpot's integration with Google+. Since it now has so many of its own reviews to publish, Google no longer needs to display user-generated opinions scraped from other websites. With Congressional hearings regarding its "monopolistic practices" looming in September, the timing was right for Google to make the shift.

On the other side of the coin, though, were websites like Demand Force and Martindale that Google may have thrown to the wolves. Much of the reason these types of sites prospered was because their reviews were featured prominently on Place pages and in the SERPs and the details that appeared on their business profiles appeared on Place pages, as well. Now, their reviews are gone, along with a prime motivation many businesses had to use those directories.

There are still links to reviews of businesses on third party sites, both in the SERPs and on Place pages themselves and review snippets from sites that don't mind it are reappearing in the SERPs are creeping back into blended local listings. More importantly, many Local Search experts agree that those third party reviews still matter in the Places ranking algorithm, even though they are not as visible to visitors as they were at one time.

In conjunction with this change, Google Place pages got a new look that boosted the prominence of Google's own reviews and added eye-catching Write a Review buttons to the pages. When the viewer is logged in to a Google account, leaving a rating on Place page is as simple as clicking on a star.

On an Android phone, a Rate this! button appears in about the middle of the screen and stretches all the way across it. Since most Android users are continuously logged in to Google, it's now incredibly quick and easy to give a rating and/or a review from right from your cell phone, as well.

As you can see, Google is no longer just serving up content it has found, indexed and ranked on the web. Instead, it is rapidly becoming the owner of a significant body of valued content. The land beneath Local Search is rumbling. Keep an eye on this trend!