I've recently posted a question on SO and set a bounty of 50 on it. My impressions was that neither the view count nor the amount and quality of answers increased significantly as a result of the bounty.
I wanted to know from your experience:
When and how to use bounties effectively?
Are certain topics better (or worse) suited for bounties?
Is a 200 point bounty significantly more effective than a 50 point bounty?
Note, this is not a duplicate of this question as I'm interested in how to use bounties effectively and not whether they are effective.