Previous marriage? Sure, tell, and then let the matter pass ... it's a dead issue.
Profile? No, dead issue.
Disclose on first date? Sure, right before you say "can we get Chinese food?" - For all of these questions, if it's a fact from your past, early in a possible relationship it's on a par with "I have green eyes." If the guy thinks it's a deal-breaker, get it out on the floor and stop wasting your time.
Still legally married? Now that's a challenge. If you have a written legal separation agreement that stipulates that you're just waiting the mandated waiting period, and if you're truly divorced in all but name only and not trying to save the marriage, I think you're entitled to date. Other people may differ. One of my previous relationships had just such an agreement, that spelled out that each partner was entitled to get on with their life and behave exactly as if they were single.
If you failed to reveal it from the beginning (if we were dating) I'd have a problem with that.
I'd also have a problem with being public-records-searched. At least, if someone did that on me, in anticipation of our becoming seriously involved (call it "due diligence") I'd wish any relationship we had supported an accurate judgement of my character without detective work. It would probably cause me to say "bye".