> If you have no robots.txt file then it's an open question.
Only for definitions of explicit I must be unfamiliar with.
If the presence of a robots.txt makes one's intent for a given resource explicit one way or the other, the lack of one (and the lack of some communication in some other channel) must mean there is no explicit permission.
That is correct, for what it was worth IBM's legal team came down on the side of 'assume deny' and Google was (at the time I was there) 'assume allow.'
Only for definitions of explicit I must be unfamiliar with.
If the presence of a robots.txt makes one's intent for a given resource explicit one way or the other, the lack of one (and the lack of some communication in some other channel) must mean there is no explicit permission.