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You can use them to "boost" (ask the Ecency curators to give a big vote to, though it's not guaranteed depending on the post, their vote value at the moment, etc) or "promote" (promotes it in people's feed who don't otherwise follow you) a post; you can do it on your own posts or someone else's post that is less than a day old. I like to do it on other people's posts since my normal vote is only a few cents, to give a bigger reward to nice posts that I like. :)

Thanks for advices. They mean a lot to me, since I'm new here, so I'm taking it slow...

You're welcome! I'm happy to help. :)