www.site.com VS Site.com

ERROR_331:
с www - ибо часть стандарта url ☝.

ERROR_331:
Согласен что в логотипе лудше без www, но во всех остальных случаях с www - ибо часть стандарта url ☝.

3.3. HTTP

The HTTP URL scheme is used to designate Internet resources
accessible using HTTP (HyperText Transfer Protocol).

The HTTP protocol is specified elsewhere. This specification only
describes the syntax of HTTP URLs.

An HTTP URL takes the form:

http://<host>:<port>/<path>?<searchpart>

where <host> and <port> are as described in Section 3.1. If :<port>
is omitted, the port defaults to 80. No user name or password is
allowed. <path> is an HTTP selector, and <searchpart> is a query
string. The <path> is optional, as is the <searchpart> and its
preceding "?". If neither <path> nor <searchpart> is present, the "/"
may also be omitted.

Within the <path> and <searchpart> components, "/", ";", "?" are
reserved. The "/" character may be used within HTTP to designate a
hierarchical structure.

Hutch:
напрашивается еще вопрос ...кто набирает адрес в виде https://searchengines.guru/.:80/ ?