So i guess a couple people started using fokit so everybody else did too. Fair enough.
As for yahoo photos there are only two options private and public. There's no in between. Which is why fokti seems like an attractive option because you specify a password for people to use. And give out that password as you like.

Personally using my Yahoo account wouldn't work for me because:

1- Everyone would have access to all of my photos (as already mentioned)

2- I don't want to have my email address floating around out there
I mean I could always open a new account but then why not just open a Fotki instead?