[rsbadger]

Essentially yes - but "previewing" link and sending that link to Bingbot to crawl and index is another matter.

Imagine you send someone a "private" link to a file...Bing sees that and indexes it for the world to see. Not cool.

[swiftcoder]

Is this actually the Bingbot crawling for the index, or do they just use the same bingbot code to generate link previews?

If I have a well-tested crawler sitting here, I don't see why I'd write a brand new one just to fetch previews in outlook...

[Gigachad]

“Private links” should be covered by robots.txt. The only case I see this happening is for those “anyone with link” shares and those are easy to cover.

[rsbadger]

AFAIK, most of those "private" links are actually just "unlisted" but they're still public. I'm sure Bing is indexing those too...

[Gigachad]

Anything private should ideally be put behind authentication. If that isn't possible, than robots.txt. Search engines are _meant_ to index everything that is publicly accessible and not blacklisted on robots.txt.