I know if a person is involved in the thread, the creator of the alerted post, or was the alerter, then s/he can't be called to that jury. Can a person who recommended a thread be called to a jury for the OP? What about posts within the thread s/he recommended?
Also, I have read this, but am not sure, if a person opts out of a jury, is s/he penalized for this?
No penalties..that is why they give you the opt out option...they know there are times when you are unable to be on the jury.
Also, you can opt out for longer periods of time by choosing "unwilling to serve" in your account under preferences.
you can always change it back to "willing to serve" at any time. I do this for various reasons from time to time.