You can refer to your own experiences or those of others. Maybe your assumptions are wrong.
That's a good question, Jeff. Unfortunately, I don't know the answer. I do have two points to make on the subject though.
1. Establishing an online presence is crucial and best done before sending out a manuscript. Publishers will Google your name and they'd better come up with some hits or, no matter how good your book is, your change of getting accepted for publication just went down the toilet.
2. Sometimes, it's not what you know, it's who you know. If you can meet publishers in person, your odds of publication just increased dramatically.
As Forrest Gump said, "And that's all I have to say about that."