Some of the deals aren't great, like $15 for a reflective leash, big deal, but they email you only every so often because they don't have a new deal daily, so at least you aren't inundated with useless deals every day.
Here are the daily deal sites for pets...
Furryboo! - Most deals so far are kinda eh, but some are very good. I got $40 for $80 worth of merchandise at a huge online pet store. The deal was available for 5 days. Loved it, so did mah pup. They've even had 2 offers for reduced Petco.com GC's as well. Worth signing up.
Doggyloot - They seem to be on the way to working it out, I've seen them have okay deals, like $25 for $50 worth of Petzlife products (an awesome product that removes plaque and tartar from doggy teeth), but offers are still few and far between, and most of them sorta eh. A promising site though imo. Worth checking out from time to time.
Trubates - This daily deal site isn't just for pets, but they have a pets section and i've already gotten 2 good deals for mah pup, including $40 for $80 worth of grooming at a pet center near me. Also got $15 for $30 worth of other stuff at the same place. Yay! AND, for all other types of deals they are great as well! Probably my favorite daily deal site next to the original Groupon. Highly recommend signing up.
Barkingdeals.com - They're new and have partnered with Dogster.com so it'll be interesting if they figure out how to make it work. Barking Deals site does PLAN have local deals in addition to their national online offers, but they haven't surfaced yet. Right now the offers are usually direct product offers you purchase from the site, but from national brands like Kong, or Petzlife. Usually half the retail price and free shipping. Definitely worth visiting from time to time.
Simplypet - so far I haven't see anything good, and the deals you get are pretty week. Like $2.50 off a Nylabone. ?. Next.
ThePetDeal - It's early in the game for these guys and they've only put out couple of deals, but the last one was for 4 walks for $20 with a commercial dog walking company, and I've seen another for $50 for a full 3 days weekend boarding/daycare at Happy Paws. : ). Worth signing up for if you live in Manhattan, NYC