Right now they exist to provide newer pieces of software which aren’t available in Debian’s Woody release.
Once Sarge is out they become obsolete overnight – as all their software should be part of Sarge, and installable without any third party repositories.
Obviously Debian development will continue and over time newer pieces of software will be available in Sid that aren’t part of Sarge, so the backports will become necessary again. But there’s definately a point at which both sites become obsolete.
I guess that means the site admins get a nice break?
Today I retired all the broken machines and pieces of hardware I have, in the traditional manner.
I took the boxes that are almost complete, stuck a post-it note on the side describing which pieces worked / and which are broken. Then took them outside my flat and piled the boxes up against the wall.
Come tomorrow I’ll go to work and by the process of magic all the spare parts and boxes will have disappeared.
I left my email address inside each of the cases, just on the offchance that somebody wants to say thanks – or will tell me where they end up.