I think I've written about this before...

Let's be clear now: I don't hate mass emails. I just fail to see the point in them, most of the time. Or, perhaps more accurately, I really dislike how they are used inefficiently and ineffectively. We used to be able to function without letting everybody know absolutely everything about every little detail about said function/cause/email subject.
I don't mind getting a mass email, as long as it contains information that does, in fact, pertain to me. However, what doesn't make sense to me is the "reply to all" function, when the "reply" does not pertain "to all". There is, after all, a simple "reply" button. Otherwise, the mailbox gets even more cluttered with information that looks like it pertains to me, but, in fact, does not.
Case in point: If you're emailed about a party, or some such thing, does everyone really need to know if one person is wondering if they could bring an extra friend, or what they were planning on bringing to eat, or what shoes they were planning on wearing, or that they are going to be one hour late? NO. Emphatically, no.
That's common sense email etiquette: don't clutter the email box. No spam, no chain-mail, no cute video or flash presentation that you had forwarded that you think everybody in your address book needs to see (not unless it directly pertains to them), no powerpoint presentation with some esoteric puppies. In light of how, increasingly, individuals are literally drowning in their emails (I think it's sad when friends have to stay home in the evening, just to clean out their email boxes), I think it's a simple public service to retain email for useful information transmittal.
This also, of course, speaks to my bias against email as the main communication method between individuals. I faaaaarrrrr prefer speaking to someone in person, rather than maintain some email conversation (Exceptions, of course, are those people who live long distances away). Of course, that's obvious: If I like you, I will talk to you. A lot. The end. The much more efficient and enjoyable way to go, frankly.