When this popped-up out of the blue, I went looking at Console logs and discovered why blocking with LS wasn't sufficient to stop these nag notices anymore.
Feels almost like getting "hacked" - this uninvited message hijacks whatever you're doing and leaves no option to be rid of it other than to click "details" and go for an inconvenient, unwanted, unpleasant, and downright RUDE ride thru some sales pitch. Right up there with telemarketing calls and junk mail.
12/18/14 10:38:54 Noticeboard[3899] Noticeboard: Launched, starting NoticeboardUpdateOperation
12/18/14 10:39:00 installd[3904] Starting
12/18/14 10:39:00 installd[3904] uid=501, euid=501
12/18/14 10:39:00 Noticeboard[3899] NoticeboardUpdateOperation: Install did progress state=0 progress=-1.000000 (-1.000000 remaining)
12/18/14 10:39:00 installd[3904] PackageKit: ----- Begin install -----
12/18/14 10:39:00 Noticeboard[3899] NoticeboardUpdateOperation: Install did begin
12/18/14 10:39:01 Noticeboard[3899] NoticeboardUpdateOperation: Install did progress state=1 progress=9.094839 (5.026250 remaining)
12/18/14 10:39:01 Noticeboard[3899] NoticeboardUpdateOperation: Install did progress state=1 progress=16.625473 (5.026250 remaining)
12/18/14 10:39:02 Noticeboard[3899] NoticeboardUpdateOperation: Install did progress state=2 progress=23.003168 (5.026250 remaining)
12/18/14 10:39:02 installd[3904] Cannot save receipts for no-authorization install.
12/18/14 10:39:02 installd[3904] efw_cache_update -c exited with 255
12/18/14 10:39:02 installd[3904] Installed "SU_TITLE" ()
12/18/14 10:39:02 Noticeboard[3899] NoticeboardUpdateOperation: Install did progress state=12 progress=100.000000 (-5.000000 remaining)
12/18/14 10:39:02 installd[3904] PackageKit: ----- End install -----
12/18/14 10:39:02 Noticeboard[3899] NoticeboardUpdateOperation: Install did finish
12/18/14 10:39:02 Noticeboard[3899] Noticeboard: NoticeboardUpdateOperation finished with notification to show:
Thanks to you guys who have identified Noticeboard.app as the culprit and revealed its location, I guess the thing to do is extract it from the System and see what happens.
Unfortunately, I'm hearing from many people who have innocently gone the upgrade route only to find it breaks older apps, printer, etcetera and leaves them unhappy (if not angry) and wondering how to fix things. Really sorry to see Apple doing this to their customers.....