I've been thinking about what I can do to keep people sticking around here longer (since it seems we've had a lot of users show up, post for a bit and then either delete their account or just stop posting altogether lately), and wanted to know what everyone thinks of the following ideas. Both would make the forum more "social", and possibly encourage users to stick around longer.

1. "Likes" system. This would allow you to "like" individual posts, entire topics, etc. It would also display a list of who liked a particular post/topic, for everyone to see, and can even be configured to show various statistics for users (their top "liked" posts, how many "likes" they've received, etc.). The only downside is that by itself, it wouldn't notify you when someone liked your post/topic.

2. "Alerts" system. This would be somewhat similar to Facebook's notification system, but like the "likes" system, would be specific to this forum. This addon would notify you (via the forum and/or via email) of actions such as people "liking" your posts/topics (if we install that as well), new profile comments (though that system isn't widely used here), new replies to topics/boards you've subscribed to (an extension of the existing notifications system) and even changes to karma (if we decide to leave that enabled with the "like" system addon).

These addons are $15 each, so I don't want to add them if nobody's going to use them

That's a pretty good idea.  I don't think everyone would use it, but I probably would! 

alerts help a lot. i hope everyone will b in favor of that.

I've purchased and installed both.

To "Like" a post, just click "like" next to the "Quote" button in each post. I'm not sure whether you can like an entire topic yet. I've also got it set so that you can't like your own posts, but this could change.

For Alerts, go to your profile, then go to Profile Info -> Alerts -> Alerts Settings to enable them. You currently cannot see the alerts notifier at the top of the page, probably due to the width of the logo. I am working on fixing this though.

I've currently got it set to refresh the alerts every 30 seconds, but this could change as well if it ends up overloading the server too much.

Hopefully this will keep people more active

Cool!  Thanks!   

Ok... The fancy "like without reloading the page" functionality should be fixed now. There were a few bugs in the code

It's actually not that difficult to install stuff. The forum software includes a built-in "package manager" - you upload a ZIP file containing instructions and related files, and it does all the work for you (though sometimes I do have to manually edit things due to conflicts with things I've already installed).