For however long now Facebook has been giving people a daily notice of their memories. Essentially a look back at the same day for up to about five years ago. I like this feature and find it to be useful.
I think the original intended function was to give people a look into the past so they can relieve fond memories and laugh at themselves a bit as well. I do this myself as well, but I also take some time to purge some things from my wall as well.
Mostly things that just have horrible spelling mistakes or nonsensical posts that I haven’t the slightest recollection as to why I put them up, but also don’t get rid of things from people I don’t associate with anymore. Some people will probably say that I shouldn’t try and erase my past and I agree with said people. However, I have learned from that said incident and moved on. I don’t need a yearly reminder of it.