phrasal verb-sign in

[Unregistered]

I have a doubt about the phrasal verb "sign in."
Consider the sentence, "I signed in to a web site." Some write it as "sign into" and others as "sign in to". Because the phrasal verb is "sign in" only, is it correct to write "sign into"?

 

[David L.]

Actually, you sign in, in order to access all the features of a website; and you do the act of 'signing in' on/ or at a website that has been found via its URL but which then requires a password to access its features.
So, "I signed into a web site." would not make sense.
I signed in on the UsingEnglish website and...
I signed in at the UsingEnglish website and...


However, we sign in at a private members' club, at work etc - 'at' only.