WWW or not

[Phenomenon]

I recetly found out that it actually matters if domains are http://mydomain.com or http://www.mydomain.com.

In WordPress i have entered my URL name with www.... but is that good enough?

Thanks in advance :-)

[Phenomenon]

I recetly found out that it actually matters if domains are http://mydomain.com or http://www.mydomain.com.

In WordPress i have entered my URL name with www.... but is that good enough?

Thanks in advance :-)