I've lost control of my email. With about 600-700 non-spam emails hitting my inbox, I've been reduced to just scanning subject lines and the "from" field to try and pull out the important stuff. And yes, I have sophisticated filtering that helps a little, but not enough. (For example, I subscribe to email lists that add another 400-500 emails a day. I've essentially given up on almost all those lists, filtered off to their little ghettoized folders.)
If you are promoting an event or cause or issue or group or candidate -- use the diaries. That's why they're there. You don't need me to act as a gatekeeper. And, in fact, I'm much more likely to pay attention to your product if you first build grass/netroots support for it (like BuyBlue, Boycott Sinclair, Crashing the States, and so on).
If you want to promote a product, buy an ad. If this site is too expensive, buy ads on other less-expensive fine blogs. dKos isn't the only game in town. And it pisses me off that organizations that were happy to advertise on dkos when it got 100K visits per day now complain that this site is too expensive, yet refuse to consider advertising on the many more blogs on the scene that get that much traffic today. There are some great values in blog advertising out there, even if this site ain't one of them anymore.
If you want to talk about the rising cost of banjos in Lithuania, then find a blog that addresses that topic. My writing is focused on elections. If you're not sending me an email about an election-related topic (or site-related issues/problems), then please, please, please don't send it. Feel free to diary it. Again, you don't need me to talk or write about it. You have the power to do so yourself.
I used to say, "I can't respond to every email, but I read them all." That's no longer the case. I couldn't read all emails I get and still have time to write. I can't even indulge my guilty pleasure of reading my hate mail (they were quite motivational).
So I focus on the stuff that is directly relevant to my job. Everything else gets flushed out.