Anything with a physical location or a local service-based business. Reviews are CRITICAL.
A bad review won't hurt you as much as how you have handled the bad review. If you are honest, own up to any mistakes and try your best to make it right and other customers see this, they are more likely to see this as favorable.
For some industries, Google Reviews are very critical. Businesses that are local in nature and are often looked for with location in the keywords. Google is also a great place to build your authority through reviews. So, having a Google Maps listing with a lot of positive reviews will always be a plus. There is no downside to having great reviews anywhere. And since Google is the world goes to discover, I would say it is pretty important.
I consult for a 7-figure ecommerce business, and here's what we've observed about reviews...
They're important, but not the MOST important thing.
To get more reviews, we will send a post-purchase email a few weeks after the product was purchased to leave a review. Most good ecommerce businesses I know follow a similar strategy (review email post-purchase).
In general, a good strategy for understanding whether something works is to observe what the most successful companies are doing! Sign up for their newsletters, look at their popups.
To give you actual data, we send our review email 30 days after purchase. We see a 51.3% open rate, and 9.1% click rate. Use these numbers as a baseline for your own numbers.
What we've noticed is MORE effective than reviews are referrals from friends. In other words, incentivizing friends to share with their friends and become ambassadors for your brand.
Since it's against most terms of service for review sites (like Google, Yelp, and Amazon) to incentivize for review you can't do it there.
However, we often do something like "give $10, get $10" using a tool like ReferralCandy (no affiliation). In fact, another company I help generated five figures in income last month through referrals alone.
Hope this helps. If you have any follow-up questions, feel free to book a call. Can answer a bunch more questions about reviews and what we've done in less than one hour.
Reviews are important in that they exert a reasonable amount of influence on the purchase decision of the consumer. While there may be a number of contributing factors, generally positive reviews result in conversions and repeat purchases. The potential customer is more than likely to use the Internet to help them decide whether or not to buy a product. It pays to work towards getting some positive mentions for better brand credibility and use social listening to your advantage!