Sorry if I sound cranky (it's 97 actual degrees here), but I think we have now set a new record in the number of disparate posts sent under a single subject line.
I think it's more likely that people will open a post if they know what the Subject will be. Or, at least, they can form a better idea of its interest and be better prepared to focus.
Moreover, all of our posts are archived at. Those who use the archive for research benefit from clear subject lines.