As a user of several Google products, the "cattle-herded" metaphor is perfect. Not a week goes by without my needing to counsel a former Picasa users nursing wounds from the great G+ herding of 2013.
The part I thought was interesting: "If I vote down a story that you voted up, your vote should count less in my rankings of stories. And vice versa. The same holds for comments."
To clarify: if an email is spam, no number of Rebumps will rescue it from the spam folder. In fact, if it was just ignored the first time, it makes it more likely to be marked as spam with every bump.
There's a wide range of urgency between sending a reminder after 3 days and ringing someone up to demand one right now. A Rebump works on a message that the recipient intends to respond to, but didn't, due to wide range of logistical reasons. If misapplied, it is the sender that will suffer the consequences.
Personally, I put a rebump on an email to someone I need a yes/no answer from. Maybe it's a proposal that needs approval. Maybe it's whether they'll be joining us this weekend for a beer (because I have to make reservations). I don't expect an immediate response, but I set a rebump for a day later (default is 3 days) because I shouldn't have to chase you down to get a simple answer.
Definitely see your point about how annoying it would be to get these one email forwards from my great-aunt, though. We are trying to convey to users that Rebumps should be used judiciously. It seems to be working so far.
As a human asking you for a response, I think I'd deserve one to my first email. I am writing the follow-ups in advance in case you starred it and forgot it, opened it on your cell and forgot to 'save as new.' Things like that.
Also, you won't know it's machine generated, though we are considering an option to add a blurb explaining that it is a friendly reminder powered by Rebump.
Would you feel differently if that were the default?
This is a future feature and we are examining which method is best and whether people actually want it. Would you adjust the content of a bump based on whether or not the person has viewed the email? May cross the Creepy Line. Maybe not. Open to feedback.