[ganoushoreilly]

Just because they say at board discretion, doesn't mean they can just arbitrarily recall your original offer (whatever the terms were). Speak with a local lawyer in your Jurisdiction. It's most definitely not normal behavior in any company.

[nibsfive]

This is not true, it really is at board discretion. Generally speaking many companies hesitate to even put stock offers in writing because of stuff like this. Whether they can do it legally (they can) and whether it's okay (it's not) are different here.