Google updates its search algorithm more than 500 times a year. For cumulative Google algorithm changes, Moz has a handy Google algorithm change history page, which highlights changes since 2000.

If you're looking to catch up on Google's most recent changes, here is a quick summary with pointers on how online merchants can still maintain a profit using Google.

The most controversial change Google has made recently involves increasing user privacy for Google searches through increased search encryption. For SEO professionals and online retailers, more organic search encryption translates to less available keyword data on Google Analytics, and more "(not provided)" keywords.

The amount of "(not provided)" data on Google is now at 81 percent:

Although online merchants can't find as much organic keyword data on Analytics, there are still multiple ways to find visitor data from organic search.

Here are three ways online merchants or advertisers can find search data (check out the full post here):

Use Google Webmaster Tools.
Consider Anchor text.
Delve into Google AdWords.
Google Shopping Product Listing Ads Local Availability

Local search is becoming a bigger priority for Google, something which Google's local update highlighted early this month. Google added local availability and local storefront features to Product Listing Ads, broadening online search information on local stores, and giving searchers access to local storefronts with product information.

Here are some steps online merchants should take to address the Google local update:

Optimize your Google+ Local Business Page.
Audit and augment your Google feed, as it powers both local storefronts and PLAs.
Include business images for the Google Carousel.
Send consistent business information to Google (as well as other search engines), and social profiles (Yelp, Facebook, Zagat).

Google Hummingbird

The arrival of Google's newest algorithm, Hummingbird, is designed to refine search results and Google's search Knowledge Graph. Although announced in September, the update was running for a month before Google officially announced it.

In addition to increasing search result speed, Hummingbird is designed to refine results for searches which mimic verbal speech, or conversational search.

Here are some steps online merchants should take to address the Google Hummingbird update:

Refine your SEO strategy to reflect verbal search (read: create quality, relevant, and original content).
Build content and product information around user needs.
Consider expanding and revisiting your customer and reader personas.

This month Google begins using Google+ user information to accompany products in the form of user reviews, advertisements, and similar material. For users, this update can be a bit disconcerting, but mimics a similar Facebook policy. For online merchants, this underlines the importance of both Google+ and customer reviews.

Here are some steps online merchants should take to address the Google+ update:

Set up or refine your Google+ business page.
Engage with users across social, especially on Google+.
Provide good quality products and customer service.
Encourage customer reviews through sites like Ekomi and via Comparison Shopping Engines.