If It’s Not an Offer Letter, It’s Not an Offer(medium.com)
medium.com
If It’s Not an Offer Letter, It’s Not an Offer
https://medium.com/@tailspin/if-it-s-not-an-offer-letter-it-s-not-an-offer-d593b08da6e6#.2k59echhc
https://medium.com/@tailspin/if-it-s-not-an-offer-letter-it-s-not-an-offer-d593b08da6e6#.2k59echhc
The situation described here is a legally-binding offer made to a prospective employee, which was then accepted (also legally-binding). When they revoked their offer s/he could have sued.
Unfortunately, you can't go around suing people for reneging on offers, at least not in the US. It's expensive, and it gives you a bad reputation.
The fact that this happened, however, means that the company had no integrity and that the person who received the offer is better off working elsewhere.