The thing that bothered me about the whole +1 feature, I am now realizing, is that it was a solution in search of a problem. That is, my sense was that LJ was mostly doing it to keep up with the Joneses, with no thought to what the actual effects on the community would be. It was notable that they never said, "Here is a problem we're trying to address, and this is the way we're planning to deal with it" -- they just said, "Here's a new feature", with no rationale presented at any point aside from the fact that Everybody Else Does it.
And the thing is, I don't actually *like* this feature on FB or G+, because it is too ambiguous. I certainly use it, but I am always bothered by it. FB's "Like" is connotationally wrong in many circumstances: what I usually want to say is, "I agree with this post" -- but there are a lot of posts on horrible subjects, where pressing the "Like" button is just plain squicky. And Google's "+1" is (deliberately, I suspect), semantics-free -- it is never quite clear *what* somebody means when they press it. Sometimes it indicates agreement, sometimes it's a cheap-and-quick way to share the link, sometimes it is simply a way to store this link for future reference.
(Of course, the truth is that both buttons mostly exist for the purposes of giving more information to Facebook and Google, so that they can more accurately profile you, to sell you as an advertising target.)
When I ponder it, I find that I wouldn't actually mind buttons with clearer semantics. A simple "I agree" button would have some downsides (in that it would reduce the impetus to actually comment meaningfully), but at least I would understand its purpose. Frankly, an "I read this" would fulfill the social-back-scratching that many people mean when they say "Like". A configurable mechanism, that let you design your *own* buttons on your blog, and choose from a palette of canned options, might be downright spiffy and interesting. (If more challenging to implement.)
This is leading me to wonder which features from the big social networks I actually *want* in LJ. The one that jumps out to me is "Share". I've wound up doing most of my link-sharing via FB these days, simply because it is so damned *easy*: click the button, type my meta-comments, and it's done. I'd love to have something similar for LJ, but of course LJ can't make sites pick them up, and nowadays they're sufficiently minor that most sites won't. I suspect the right answer would be for someone to implement this as a browser plugin that detects the presence of a Facebook "Like" button and injects the LJ version. (Or possibly just adds a right-click that lets you Share any page via LJ.) Does this already exist?
Anyone have other ideas? LJ's comment system is vastly better than FB or G+'s, and it had the concept of distinct flists long before they picked the idea up. Are there any other features of the other social networks, or variations thereof, that you think would be positive additions to LJ? And for that matter, what features *have* you always wanted to see on LJ?