Is there a list of "things" (not sure of the terminology?) people have built with it?
I guess the downside is that you can't virtualize it (I realize that is kind of the point, but it does reduce the accessibility of it).
The project is new: I and other open source contributors are currently under contract to build a Network Functions Virtualization platform for Deutsche Telekom's TeraStream project  . This is called Snabb NFV  and it's going to be totally open source and integrated with OpenStack.
Currently we are doing a lot of virtualization work from the "outside" of the VM: implementing Intel VMDq hardware acceleration and providing zero-copy Virtio-net to the VMs. So the virtual machine will see normal Virtio-net but we will make that operate really fast.
Inside the VMs we can either access a hardware NIC directly (via IOMMU "PCI passthrough") or we can write a device driver for the Virtio-net device.
So, early days, first major product being built, and lots of potential both inside and outside VMs, lots of fantastic products to build with nobody yet building them :-)
Is that a good use case for Snabb Switch, or is there is an easier way to accomplish what I want?
If you can express how you want to filter with a fancy pcap-filter expression the tcpdump is the easy answer. Otherwise you might want to code it up in Lua with snabbswitch.
Here is our basic trace store/replay library today: https://github.com/SnabbCo/snabbswitch/blob/master/src/lib/p...
Thanks for the very cool project! I will have to learn more about it.
Network Functions Virtualization is the idea of replacing networking boxes (Cisco, Juniper, Ericsson, F5, ...) with virtual machines running on your own PCs. This is basically a "private cloud" but with emphasis on doing networking in a way that doesn't annoy ISPs.
Rest assured that Software Defined Networking will be redefined to mean whatever the next good technology turns out to be :-)
In my experience high-end systems choose hardware to match software, so you only need to support one suitable option. The main reason we would add support for a new NIC is if it turns out to be better in some way e.g. as Mellanox support 40G now and Intel don't.
In Snabb Switch have a lot of 10G/40G NICs online for people to play with now: https://groups.google.com/d/msg/snabb-devel/PXOsv0uLQCE/HjPj...