I used to write detailed posts for a site called "Metro Blogs", where I did a lot of detailed posts, with photographs, documenting Bangalore...they closed down without informing me.
Deccan Herald deleted all my archived articles. No article shows up now when I click on the link.
Photobucket suddenly went from being a free site for 3rd party hosting, to demanding $400 per year. I have 5 accounts, there is no way I can afford that amount. I can't see any of my photos there now, and have lost years of blogs as well, as a result.
I'd saved all my music on a site called Muziboo. They did warn me they were about to close down, but I did not know how to port all my songs, so lost them, too.
I lost a lot of posts when Citizen Matters first had a server crash, and then when they moved to Word Press. Still struggling with many posts.
So I for one do not believe that anything on the net is there forever! They all pass away, just as I will, some day.