Google announced the update on August, 1st:

This week we released a broad core algorithm update, as we do several times per year. Our guidance about such updates remains the same as in March, as we covered here: https://t.co/uPlEdSLHoX

— Google SearchLiaison (@searchliaison) August 1, 2018

This was a global core algorithm update. On August, 8th, Google's Danny Sullivan confirmed that the algorithm update finished rolling out:

It's done. That said, we always have changes that happen, both broad and more specific.

— Danny Sullivan (@dannysullivan) August 8, 2018

The SEO industry has given this update the nickname 'Medic Update' (the below for the reasons).

It seems that this update mainly focused on YMYL (your money/your life) websites. However, websites from other industries were also hit.

Google defines YMYL pages as pages that can have an impact on your financial or physical well-being, for example:

• Pages that solicit personal information, such as personal identification numbers, bank account numbers, drivers license numbers, etc., which could be used for identity theft.
• Pages used for monetary transactions, on which users might give their credit account or bank account information; for example, any page that allows you to buy something.
• Pages that offer medical or health information that could impact your physical well-being.
• Pages offering advice on major life decisions, such as pages on parenting, purchasing a home, a vehicle and so on.
• Pages offering advice on major life issues that could impact your future happiness and finances, such as pages giving legal or financial advice.

As websites from the medical sector experienced the biggest ranking changes, the ranking algorithm update was named the 'Medic Update'.

If your website rankings have dropped, then your website has not been penalized. Google's algorithm just found that other websites have more expertise, authority and trust (EAT) than your website.

There is no single fix that will solve the problem. There are several things that you can do to show Google that your website should get higher rankings:

1. Remove all technical errors from your web pages

2. Improve the design of your website

3. Improve the content of your web pages

4. Improve the links that point to your web pages

"If you search for a business at a location, you will see a mix of local search results, as well as organic results that Google believes, are relevant. [...] A recent patent from Google explains how that kind of demotion might happen, in a patent that focuses upon distance based search results.

"Links to your site are viewed as a “vote” for the quality of your website. The disavow tool tells Bing you don’t trust and want to distance your website from inbound links from a specific domain or directory on a separate URL.

Both Bing and Google recommend that webmasters reach out to remove as many spammy and low-quality links to your site as possible before disavowing links. However, if you’ve exhausted all options and aren’t able to make headway on getting links removed, you can use the Disavow Links feature."

Editor's note: You can create a disavow links file with the Link Profiler tool.

"According to [Google's Danny] Sullivan, asking for a link is fine. [...] Sullivan also talks a lot about intent, and he feels that site owners should not be afraid to ask for a link.

He says the difference is when it is moving into whether you want the link for content just to help rank, but unless it is an extremely well known and respected publication, it’s extremely likely that someone wants that link for the SEO value and not just the traffic."

"Sure, Google is still bigger, but [...] Bing has been introducing significant innovations. [...]

Bing’s product improvements are good for brands and good for Google because healthy competition keeps everyone on their toes. Bing’s improvements also help business owners and search marketers in their optimization efforts. Let’s take a look at a number of Bing’s improvements and how we can use them to promote our businesses."