There's a similarity between bombarding media outlets with press releases and having your mailbox inundated with flyers. I don't know about you, but when I reach in and pull out a handful of flyers, I give them a very quick once-over and discard most of them immediately.
The same fate awaits most press releases, particularly with large, busy media outlets. Large metro dailies, radio stations and tv stations get hundreds every single day, sandwiched in between those Viagra/Stock Market/Pharmeceutical mailings.
Realistically, I think the smaller, local media outlets are the most likely to respond, particularly if you play up the local-boy/girl-makes-good angle. I think you will also increase the odds of someone actually reading to the end of the release if you include the SOS logo at the top of it. It's catchy and should pique interest.
I think if we get a 5-10% response rate we'll be doing very well.
I hope this doesn't sound discouraging. It shouldn't. We're competing against well-oiled, seasoned, and deep-pocketed publicity machines (and the aforementioned bot-generated spa**ers).
Where we can do the most 'damage' I believe, is in utilizing our own personal networks of friends and family, as well as our own sites, newsletters etc. to generate and sustain a buzz. Once folks actually get the book in their hands, read and enjoy it - they'll hop aboard the word-of-mouth express.
Although the raison d'etre for the book was situationally and time sensitive - the book itself is not. Its merits lie between the covers and are timeless.
Don't be disappointed if we don't make a giant, immediate splash. SOS has legs and will be selling for a long time.