Very cool. One suggestion for the product page is some simple use-cases for why you'd use such a service. Also, are there size constraints for the dweets?
Basically any device or thing that has an internet connection can publish information about itself so that it can be consumed externally. For example if you had a BeagleBone microprocessor monitoring temperatures and you wanted to share those temperatures with other people or machines on the cloud, you could do it easily with dweet.io. It's basically a really simple pub/sub platform.