I remember Greenwald being known for being an outspoken, opinionated writer. Maybe his Twitter presence today projects a different image than his blogging presence back in the day. But I was under the impression that Greenwald tendency of "railing" about things, like the Iraq War, was what made Snowden aware and trusting of Greenwald:

https://thetyee.ca/Books/2014/05/30/No-Place-to-Hide/

> In my own exploration of the blogosphere over a decade ago, I soon ran across Glenn Greenwald. In some ways he seemed to break the rules of writing online: he wrote long blog posts composed of long sentences in long paragraphs. His blocks of text did not welcome, but I read them anyway. So did thousands of others.

> In the process of blogging, Greenwald helped form a community of interest, just as opposing communities formed to support Bush and his policies. In forming his community, Greenwald eventually drew the attention of a young man who’d been mostly hanging out in techie communities: Edward Snowden.