I was going to say that you should never put sensitive information in (unsecured) email because of things like this. "Never write anything you wouldn't want printed on the cover of the NY Times" is sage advice I've heard in the past. Unfortunately, the standard of what is acceptable is quite subjective - I don't see anything objectionable in Podesta's emails. If I were him I would see them as innocuous - and yet, here he his, taking a serious hit from it all.
Now, the question is, where the heck are the Republican email leaks? At the very least, it would be interesting to compare...