Never forget your password again (Hashing)
getvau.lt
getvau.lt
site: 1twitter
site: bump-facebook
Just use a bumping method, it isn't the best... but it works. You could always change the number of characters around also.
And its pretty much the same thing isn't it - different salt vs bumping the site name.
For example,
twitter#username facebook#username
to
twitter-username facebook-username
Edit: - Is it open source? Shouldn't be hard to replicate, but I'm just wondering....