In 2004, I attended Ryan McBride's talk about PF, a BSD licensed packet filter.In 2005, I learned about spamd at a talk from Bob Beck. After the conference, I deployed spamd at home -- my spam count dropped to almost zero. Spamd uses PF to block spam at the IP level. This saves resources on your server because you do not actually receive the mail. Adding packet filtering features to the base operating system has enabled new applicaitions, like spamd, to develop.In 2006, I attended the Debugging Kernel Problems tutorial (PDF) given by Greg Lehey-- I continue to use these debugging tricks when debugging FreeBSD kernels today.I attended Pawel Dawidek's ZFS talk in 2007. Today I use FreeBSD/ZFS on my home NAS -- I wouldn't think of running my NAS without the features of ZFS. I want my data to have data corruption detection. It is fantastic that a production filesystem can work in my tiny NAS! In 2007 I also saw the brilliant Poisonous People talk by Brian Fitzpatrick and Ben Collins-Sussman. Part of this talk is about avoiding bikeshedding -- it was funny to watch when Fitz and Ben realized that Poul-Henning Kamp, the author of the original bikeshed email, was attending their talk.2009 was a good year for NetBSD and filesystems. There was a talk about WAPBL a journaling filesystem in the NetBSD tree and RUMP -- a framework that allows NetBSD kernel filesystem code to execute in user space.2010 showed BSD continuing to be used as a platform for OS research. Kirk McKusick's new Journaled Soft-Update improvements now allows fsck in a few seconds, instead of hours.