Whisper Systems failed big once again. They just announced their "Desktop" version of Signal, which is actually a Chrome app.
So just to get facts straight, this is neither a Desktop nor a Web app. And just like their Android app, you need a Google account to download it.
Actually this is even worse, because you also need to use Chrome to use this app. Channeling all your (meta)data through a closed source browser, built & distributed by the biggest tracking ad company.
If you care about privacy, Signal is certainly not an option.