The Blog Graveyard- where blogs go when they die

OK, so I try to keep things upbeat most of the time.  

This is not the beginning of a series of depressing posts by any means.  I am just curious about some of the blogs I follow and I wonder about their longevity.  I don't want them to go away 'cause I enjoy reading them but I have come across many that have folded up and closed shop recently.  Also, I have come across many that croaked months before but their pins or posts or presence is still online with good content, making me wonder- "Where are they now?"