An Appcoin is a type of cryptographic currency that is meant to only be used for a single application. Unlike traditional, general-purpose cryptocurrencies (like Bitcoin, Ripple, Ether, etc) an Appcoin is intended for only a single purpose.
There is nothing wrong with Appcoins per se and we fully support experimentation with Appcoins to find appropriate uses for them. However, it can be easy for developers to use them as a crutch, and there is always a danger that an unscrupulous developer may use them indirectly as an opaque fundraising mechanism, building applications that lack a clear description of the fees they impose on the user.
If you have found a way to appropriately use Appcoins in your application, then we wish you the best...
...however, if you are building a dapp WITHOUT Appcoins, we want to salute you with this webpage!
By not using Appcoins, it means your dapp likely has a transparent fee structure for users. Also, it means you are building a Dapp that is free, self-funded, or has received capital from investors in a more straightforward manner than is possible with an Appcoin presale. Congratulations for building a dapp free of Appcoins!
Here is a public domain logo we have created that you are welcome to use (and feel free to link your dapps to this page if you find this to be a helpful selling point for your dapp!)