4

Yes, you lose reputation for downvoting answers (but not questions). See this post on the central meta for more discussion on this.


2

It seems as if your rep change this year is 1,523 rather than 539: And that puts you on page four on the list of all users:


2

If you down voted an answer then you lose 1 reputation point, which is only viewable to you. Since I can't see this on your own reputation page I'm guessing that's what happened. You will probably be able to see it on that page though (and any other reputation change history of yours). You can't lose/gain reputation for comments in any way.


2

This is due to the recent reputation change that Stack Exchange has made. Question upvotes are now worth +10 rep. Read here for more information.


1

The number on the reputation tab on your profile is the amount of reputation you've gained since the last time you personally clicked on that tab. That fits the pattern with numbers on all of the other tabs.


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