We had a lady at our office die over the weekend. She lived alone and had no real family. When she didn't show up to work on Monday, a couple of employees went to her house looking for her. They found a note on the door from the coroner stating that she was deceased and that if anyone knew next of kin they should contact the county coroner's office.
Apparently she was able to dial 911 as she had the heart attack, so at least they came and found her, and she didn't just lay there all weekend, but it's still so sad that she didn't have anyone close enough to her to even know she was gone.
That's pretty much why I want to make sure I die in an explosion big enough that it's visible to a 100-mile radius. That way whether or not you knew me, you'll definitely KNOW when I'm gone.