I have as I had a couple who I did not know who they were as I did not recall posting with them. It usually was that they were in the same threads and I did actually usually enjoy their posts.
i like to notice patterns. theres a particular person who is always on my recent visitors list...stalker style. poor girl
I do if its a name I don't recognise. But I must have a selective memory or something because quite a lot of the time when I get there I realise that I have read their profile before. So if my name appears on your list quite regularly you must be one of these instantly forgettable peeps.