A couple of years ago I was talking about a steampunk novella I'd set in Western Australia and how it was a total coincidence, but I'd set the story in the same year my great-grandfather arrived in the colony. Then I went on in another post to share the newspaper clipping of my great-grandparent's wedding (it's here, but a little bit of scrolling is necessary -- Trove is a wonderful resource for researchers).
Well, this morning I opened my email and discovered a message from a very distant cousin in Europe. She'd found me via that post and it turns out our great-grandmothers were sisters.
It just goes to show, you never know what a blog post might bring you :)