Please post your tag synonym suggestions as new answers in this thread, one answer per suggestion. Upvote answers where you believe that the suggested tags should be made synonyms, and downvote answers where you believe the tags should remain separate. Well upvoted suggestions will be eventually implemented by the moderators (and then the corresponding answers will be deleted).
I am the top user of volatility-forecasting and do not see why it should be separate from volatility. volatility is shorter and more general. More general is a benefit, as there is not enough trafic in the tags for justifying this fine of a division. I thus propose to make the longer, more specific tag a synonym of the shorter, more general tag.