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Your upvotes should not be causing others to lose value. Sometimes it may seem that way if the value of SBD falls in between the refresh.
You may "power up" from steem to steem power. You also gain steem power as rewards. Check steemd.com/@rolf.bakker to see what % voting power you sit at. If it's too low it won't be worth much.
They are currently working aon a more structured way of managing tags and followers. I don't know the specifics, but it's in the works.

Thanks for your constructive reply.

Anytime. I'm always here to help.