LOL you asked the million dollar question and it's been asked over and over and always has people puzzled.  It's almost our equivalent of "chicken or egg...which came first?"

Anway, in general the staff chooses them and they try to choose posts that they thing are interesting and relevant to a broad AR audience and will either help teach the community something or create some robust conversation or are just plain interesting.

As we "like" posts, they are more likely to get featured, esp when lots of people like them. They use this as a gauge to flag popular posts.  They may also use reblogs and bookmarks to help w/ that.  Soon, (I think in Feb), they are looking to semi automate some of it, so that those w/ a lot more activity/likes make get there on autopilot.

"trending" seems to be those w/ the most comments over a certain period (maybe 30 days?).  It's not really trending to me...they should just say "most comments."  That's my opinion.

It's done by the man behind the curtain-which I'm told we should ignore.

I don't believe it is based on content or likes. I've seen a post with almost hundred comments, many likes and no gold star. We discussed the mystery of feature many times and I never got a clear answer.

AR Gods know...

great question Hank , hope you enjoy the game

This is a very subjective process and I would vote to eliminate the featured recognition.

Someone at ActiveRain chooses it to be featured : )  I know you were probably looking for a little more than that - I've noticed trends among featured posts - quality posts by new members, member milestones, "how to's", FAQ's, and hot topic/current event type blogs are often featured.  Based on what I've seen, it's quality content in a good format that usually makes it to the feature page.

Now this is one secret I would never know! Must ask ActiveGods!

That is unknown to most of us.  However, the prolific writers get the most features.  Some people think it is just the people with all the posts that get feature after feature.  That is not true it is because of your writing skill and topic that get the job done.

Nobody knows.

No idea.

That is up to 'them'!

By those in power.

It's a crap shoot of sorts. Good content helps, so does timing.