I, like many people, are on facebook alot (way to much!) and I have grown to love the "like" feature, or on other sites the "smile" feature, or "thumbs up" type of thing. Its a really simple and effective way for someone to show that they support or agree with you. Its a supportive and positive feature. Being able to like peoples threads or comments would be pretty cool. I'm not sure how I feel about threads, more so comments. Also (don't kill me here cog!) I think a very lightly moderated forum would be cool. Basically a "free for all" forum under the pretenses to enter at your own risk. Obviously things like pornography or any racist propaganda, things of that nature would be NOT allowed. I understand why this is a good thing, it will increase member activity and probably bring in more members. However, I understand why this is a bad thing. Fights, etc can tear apart relationships on the site and cause unnecessary drama. It's all about how much you trust your members and how much freedom you think they deserve. I'm saying these suggestions only in the interest of helping the site. Although I'm not as much of an active member as I once was, I still like visiting here.
Do you mean the reputation next to the report button? Your suggestion is a bit similar to that. I think more members stay long whenever they feel their posts are valuable whenever someone clicks on his or her reputation icon and add a comment on it.