If you've posted some flyers on telephone poles, once a month or so, they'll remove them. Make sure to put posters up again if that happens.
Also, leave some sort of contact info in your craigslist ad. Emailing through this site is hit or miss....not reliable at all. That or try communicating directly here through your postings.
Remember to delete your ad or post another ad letting us know you found your pet.
If you've lost/found a cat in NH: catfinders.org.
If you've lost/found a pet, give your info to animal control officer, local vets and.