Like, Retweet or Reply?
This question comes up a lot – is it better to "Like" a tweet you like, or "retweet" it. And what about "@reply?" Here's the bare minimum that you need to know:
Like on a tweet is more often than not, used as a bookmarking tool where you keep Tweets that you find relevant, and have links to content that you'd rather read later on your tablet, laptop or smart phone.
One of the most relevant differences between Twitter Likes and Twitter Retweets, is that Likes have their own tab in your profile, unlike Retweets, which you probably have to scroll down the stream to find them since there's no filter for that (by default). You can even create an RSS Feed for Twitter Likes.
Retweet means you're resending someone else's tweet to all of your followers. They in turn can retweet it to their followers. You're showing "action" on your tweet stream (without having to think up something clever of your own) and at the same time making the person who tweeted something very happy (we all spread the word with re-tweets!).
Then there's the @reply option. The main difference between @reply and retweeting is that you can't say anything about the original tweet in a retweet, sort of like clicking Like on Facebook without writing a comment. @reply lets you reply to a tweet AND say something about it.
When to Use Which:
If you just want to share a cool article or joke or quote or link that's been tweeted, use Retweet; plenty of tweets don't need your commentary (and it's the fastest way to share and tweet).
If you need/want to refer to the link in the tweet later and have it be easily found, Like it so you can find it easily. (You can see there's an option for Likes right in your menu bar).
If you want to participate in the conversation/topic you're thinking of retweeting, use @reply to give you that option. It's the easiest way to get attention from thought leaders and connect with followers who share your interests.