I noticed this, from a site change log a few weeks ago:
I'm having trouble this morning with posterid searches and wonder if that change has anything to do with it. Search is now returning many posts not by the posterid, and I don't recall this ever happening before. It is also returning threads that (presumably) also contain posts by the posterid (but also, some single messages that simply are not by the posterid).
Furthermore, if I do a search using posterid:J_catlady in my group, I get back a much larger number of results than when I do a search on "all posts by this member" (which uses the posterid # as opposed to handle). The latter ("all posts by this member") is the correct number, and only messages by me are returned.
I'm bringing this up here rather than as a bug report to support because I think there may be a problem with the intended implementation. I don't think a search on posterid should return threads at all - just messages. (Others may disagree.) But either way, something seems not right here.
Messages are the sole opinion of the author.
I wish I could shut up, but I can't, and I won't. - Desmond Tutu