Having your physical address on your website has always been important, but it is getting even more important now.
Visitors look to see if you are a real business by checking your address. If yours is a local business doing business with local customers, then having your address helps your rankings for local search phrases. Not having a posted address is a signal to the search engines that your business may not be a real tangible business and actually hurt your rankings.
Visitor Trust: Nobody wants to be scammed so people look for signs that you are a real business. They immediately look to see if you have an actual address, not a PO Box. After all, what happens if something goes wrong with a transaction? If you don’t publish your address, many will just quietly leave.
It is easy today for visitors to virtually visit your business. They just need to enter your address into Google Maps and then they can zero in with a satellite view and then move to a street view to see your store front.
Local Search: People search for local businesses and having your physical address on your website helps your business come up in these local searches. In addition to your physical address(s), list the cities you serve. Even better would be to dedicate an entire page or pages to each area you serve.
Search Penalty: Google has been getting more aggressive about cleaning up their search results and getting rid of duplicate content and low quality pages. Expect to see sites that hide their address get pushed down or excluded from the search results. This will affect anonymous websites such as affiliate websites.
Best practices would be to not only list your physical address and your phone number, but to be a bbb.org member which gives you a verified address. Your address should be on every page of your website, not just on your contact page.