I've built a service that I called Gravacoin: http://gravaco.in
Basically, what it does is that it to stores all the addresses that you register and builds you a profile with it.
It's completely free and there is no need to create an account.
You just fill the form in the homepage and then you receive a token with the activation link to validate the address that you have created.
Then you just need to share your profile URL (which you can get by hashing your email or using the search page).
You can see an example profile page here: http://gravaco.in/458641ed4b2725b16edbf0192ca0b2f2
If you built a great service, or made open source projects
Instead of inserting plain text in your README, you can use Gravacoin's badges pointing to your profile to tell people which currencies you accept and what your addresses are.
The profile page is meant to be a kind of donation page
If you are a developer
I made this project completely open-source, so feel free to contribute here if you want: https://github.com/jorge-d/Gravacoin
There is a JSON API, the full documentation is available in the Github Wiki.
In any cases
If you like the service, or even if you don't, I would love to get feedbacks so that I can improve Gravacoin !
Important point
Your email is never disclosed to anyone.
Like Gravatar does (http://gravatar.com), I use the md5 of the email to create profile links.
It means that if someone knows your email he can get your profile link, but knowing your profile link won't enable anyone to get your email (and you can check the sources to ensure that
)ps: I'm running a lottery. Everyone who registers his Dogecoin address before Monday 14th April will have a change to get picked. The winner will get 1k Doges !