In recent times website traffic to my business site has decreased. I'm told by someone "knowledgeable" that my robots.txt file is turned off and that I need to turn it on immediately. A search of my website indicates I don't have a robots.txt file there at all. I think when I built the site many years ago that I thought everything on the site should be crawled so I never included one. Should I include a robots.txt file that disallows nothing and allows everything or is that silly? PS I'm aware my website is old style and not mobile-friendly.