Back in the old days every serious business had its own website. Personalized websites are good for displaying contact information because the webmaster has practically unlimited space to display such details in any manner and as frequently as the business owner may like. In the present day most businesses, including SMEs and sole proprietorships, use social-media sites like Facebook instead of building a site of their own. Facebook is "free" and a great tool that is patronized by over a billion people, but using such sites, which are based on templates that offer only restricted malleability, comes at the cost of being limited in terms of how much data you can present, how and where it is presented, and in some cases you have to possess a certain level of computer knowhow, an attribute not all small business people possess or readily have access to, in order to effectively get your information displayed.
That being said if like most of us you are using sites like FB to advertise your products and services then at least make sure your basic contact information, especially phone number and location, are properly updated so that visitors who desire so will have an easier time contacting you. Today I visited the FB pages of two homeys whose information I was adding to the GHfind database. In one case I had to dig through personal messages dude sent me in the past in order to obtain a contact number, and with the other both contact numbers he has displayed don't seem to be functioning. I'm not trying to make it sound like my phone is always on, but if it's not there's always my email or various other ways I have listed whereas I can be contacted almost immediately.
There really is no sense in having a Facebook business page that is devoid of contact information, and if the only way a client can contact you is through direct messaging then please try to check your messages regularly - at least once a day - and like actually respond. Business owners who may not be computer savvy enough to accurately input contact information on social-media sites need to employ the services of someone who is, or even better I still hold to the contention that regardless of how many sites you may be registered to if you're marketing to a global audience it's still more advantageous to have your own. Visiting a social-media site for business information is like going to a fast food joint where the entire menu is displayed on a billboard over the service counter, but having an entire site dedicated to your business can be like dining in a fine restaurant with a 10-page menu.