If you knew someone in a non romantic way who thought of you as a friend.
And who cared about you as a person.
And thought you were special through words and acts of thoughtfulness.
And one day they said I Love You.
How would you feel?

Weird because I don't know you at all?

It would depend on how well I knew the person and in what context it was used.

There is no need for you to be cryptic. Why don't you just tell us the story.

Love is a very useful and also very vague word. I love my four cats, I love my children, I love my mother, I love certain authors, and I love Bbq chicken. If a dear friend, even one of the opposite sex, said "I love you" (and they do), I smile and tell him I love him too.

Even same-sex friends say that without getting romantic.

I hear u! I would feel little awkward bcos they said ''I love you'' now suddenly, but not while doing there daily act of thoughtfulness. But I'll take it in a positive way and will say 'love you too' my "FRIEND". :)

Depends on how the relationship was developing and/or changing. What were your feelings to them. Was it changing toward a more personal relationship?