Why do some bloggers quote themselves?

I didn't look at what holysmith did, but I think sometimes it's done in order to carry on a conversation (or a point) that was made earlier. Since people might have read the other blog post quite awhile ago, quoting something from the first blog post on the subject helps to jog reader's memories and get them back into the groove of what's been said before so that the conversation can continue from that point, rather than starting all over again.