I decided to try out MUSO, a service that will send out DMCA take-down notices to pirate sites for $15 a month. I don't think pirate sites have a big effect in my bottom line, but I do think they should respect my copyright. I do not, personally, want to spend any significant amount of time tracking them down and sending notices. So this seems like a reasonable solution. I will let you know how it goes.
Curtis Agency, E-Reads Launch Program to Neutralize Pirates
ETA: The first thing I have noticed is that they processed my payment before verifying my account. So technically I am now paying for a service they have not yet decided to provide.
ETA#2: Campaign is now live and has flagged its first pirate who is offering literally every one of my ebooks and about 100 others as one zip file.
ETA#3: I've already burned through 21 of my 60 monthly take-downs. Found copies in Spanish with new cover art (not authorized). Interesting.
ETA#4: So far I am very happy. Muso posts a list of detected files. When I check many are already down so I opt to 'ignore' them to save my 60/month. Most of the rest came down very shortly after hitting the 'take-down' switch. The link stays up so you can confirm they are really down. If they stay up you have the option of sending a reminder. Only successful take-downs after sending the notice count to the 60 limit. I suspect I will continue to use this service on an on-going basis.
ETA#5: I get a real feeling of progress from things like this 4Shared notice: "'Emily Veinglory - The Nameless God.pdf' is unavailable. This file is no longer available because it's identical to file banned because of claim". So you don't have to keep telling 4Shared to take down the same file over and over again. That's nice.
ETA#6: No new infringements posted in five days. It is not looking like I need to keep this service on full time. I will try a search later to see if I can find any that they are missing.