Folks, we now have a JIRA system vote for this issue active, requesting that the Lindens implement an optional message Inbox that we can browse when we log in - with different colors for different types of messages - and even a little icon for group announcement attachments. If people could go to SL's JIRA system at the link below, log in with your SL username and password (the link to log in is in the upper right on the JIRA webpage), and then vote (the vote link is in the lower left once you log in to JIRA), then we can show the Linden staff how serious we are abotu wanting this improvement.
Basically it would be a standard Inbox window, like any mail program, instead of tons of bothersome "alert notices" that we have to click on over and over if we are receiving a lot of offline traffic from groups or friends each time we log into Second Life. It would also solve the problem of losing such messages and transaction information if we crash a moment after logging in but before we get to check all offline activity.
Please vote here:
"Inbox for notices, offers and alike":
http://jira.secondlife.com/browse/VWR-4117
(cut and paste the link to your browser, since links still down work in the SL forum for some reason)