What does the bar of hearts mean?
The bar of little pink hearts under your username shows a ranking of the number of posts you have made, compared to other users on the site. The number of hearts indicates that you have made it into the top 10, 25, 50, 75, 100, 150, 200, or 500 posters.
The bar is just supposed to give you an idea of how active the person is on this site, and how busy the site is. For example, based on the fact it takes well over 5,000 posts to break into the Top 10 posters, you can conclude that we have some very loyal and prolific posters!
I want more hearts!
Please do not make a lot of nonsense posts to increase your post count. No one will be impressed with your post count if you never contribute anything meaningful. (This doesn't mean short posts are bad; posts of welcome and support are always appropriate, no matter how brief.)
Why did I lose hearts?
If other people pass your post count, you may move down into a lower group. For example, only 50 people can be in the Top 50 group, so if #51 passes #50, then she will go back to being a Top 75 poster. Hearts are not really "earned" or "lost", they just show a current ranking.
Should I worry about how many hearts I have?
No! This is not a competition, and you cannot control how often other people post, anyway.