A Google Hangout was spotted by John Lincoln from Ignite Visibility that confirmed that Google will be using URLs or domain names within content that are unlinked (this means links that don’t have the href attribute) to discover new pages of content and index them.
John Mueller from Google added that, although no PageRank or trust is flown from unlinked URL or citation, Google will probably use it for content discovery.
Here is the video where John Mueller confirms this:
“We use those kinds of links to try to discover new content. So for instance if we see that someone has been writing about a new domain name and we can recognize that as a domain name in the text even without a normal HTML link there, then that is something where we will try to pick that domain name up, try to crawl it and index it and see if that is something worth including in our search results.
Sometimes it happens that we pick up a whole URL like that. Sometimes someone will try to shorter a URL with just a ‘…’ in between and we try to crawl that URL so we get it wrong. But our goal here isn’t necessarily to pass any pagerank, which we don’t do with those kinds of links. But rather discover new URLs that we haven’t seen before. And if we see someone write about a URL that we haven’t seen before we will pick that up and try to index that for search.”