Many instances have domain names that look invalid and/or like scam sites to non-techies. Dot world? Dot social? Dot [obscure country TLD]? There's also no guarantees that the domain will indicate that it's a Lemmy site. Both of these become problematic with sharing, as the default (? been a while since I've used the web interface) share function links to the poster's instance and not the community instance. A year and a half ago, the shared links section in my messenger was mostly a Reddit flood. Today, it looks like someone spilled alphabet soup.