szimek
It's really great that people are still using it, after almost 6 years since the release! It was first announced here on HN: https://news.ycombinator.com/item?id=7468328. Fun fact: on the same day Facebook announced Oculus acquisition ;)
Also, sorry that the service was down for some of you yesterday - it's using a free Firebase account that has a limit of 100 connections - usually it's enough.
Do they provide a way to send audio via WebRTC or WebSocket from a browser?
Pusher has really awkward presence management that requires you to store user state on your own server, if I understood their docs correctly.
PubNub had similar issue as Pusher, though very recently they released a new feature that allows you to broadcast user state changes without having to store it on your own server.
Firebase is in my opinion the easiest one to use, especially for presence management, because it's a real database and not only a messaging service. It's also actually really easy to use for private messaging as well, even though I think it wasn't originally designed for that. We've changed PeerJS library to use Firebase for WebRTC signaling, which is basically a form of private messaging. We've also used Firebase in some of our previous projects - e.g. https://github.com/cowbell/presence-firebase.
If you're interested, you can check out the relevant source code for presence management at https://github.com/cowbell/sharedrop/blob/master/app/scripts... and WebRTC signaling at https://github.com/cowbell/sharedrop/blob/master/app/scripts....
ShareDrop in theory should be much faster (especially on local network) and more secure, as it sends files directly between devices without any server in the middle.
However, it's already possible with similar WebRTC based services like https://www.sharefest.me/ or https://rtccopy.com/.
At this moment the app works only in Chrome and Opera, because Firefox doesn't support HTML5 FileSystem API. There's a polyfill for that, but we had some issues with it, so we've decided to release it anyway. We'll continue working on Firefox support. The whole source code is available on GitHub (https://github.com/cowbell/sharedrop), so anyone can help.
Show HN: HTML5 clone of OS X AirDrop – Easy P2P file transfers in a browser
Good idea though, I'll have to add form for credit card details :)
Using Bézier curves, but with variable width, can give nice "handwritten" feel to it - http://szimek.github.io/signature_pad (works best on touch devices).