Thanks everyone for weighing in, it's been helpful and informative. I live in Colorado and when I contacted the state (vs earlier I called my city and they had no clue), I learned that anyone boarding dogs (traditional kennel and even a "Rover" private home) is required to have a boarding license ($400 annually) and a home inspection ($50 annually). I haven't followed up about a business license, but that may be something else that is required.

Considering that I was only looking to board a dog here and there, I don't really want to spend $450 / yr every year and will probably drop out as a Rover sitter. I would not like the feeling knowing that I'm not compliant with the "law" and could be subject to fines or an investigation.

Anyway, I know the Rover sitters I've used to board my dogs don't have a Colorado license # and that doesn't bother me at all. My preference is to use Rover sitters for my dogs and I'll continue to do so, it's a great service :)

Following the Rover suggestion, I posted my services as a sitter on Craigslist and provided a link to my profile on Rover.

I was harassed by someone who likely runs a traditional kennel and this person said she'd turn me in for not having a license. I called my city animal control and they had no idea what I'd need, if anything.

Has anyone else had an experience like this when trying to post an ad on Craigslist? Or otherwise been harassed by someone who isn't actually looking to board their dog?