O'Reilly's Long Snout concept is very interesting.
It's long been easy to snipe at O'Reilly as a vanity publisher for techies, but the economics of book publishing have changed to make tiny production runs or even print on demand realistic propositions. In this situation O'Reilly's shotgun approach makes a lot of sense.
Thousands of titles means they cover all bases, and being first to market in these days of Web 2.0 hypery and the ephemeral nature of many technical subjects makes a rapid publication cycle essential.