March 28: this week in social media

Every day we all see, hear or think of things we need to remember. Usually we grab a pad of sticky-notes, scribble a reminder and put it on the desk, the fridge or the relevant page of a magazine.

Mentioned on Mashable this week, Facebook has started testing threaded comments on the Web version of the social network. Rather than posting a replay at the end of a long string of comments, this allows Facebook users to directly reply to comments within a conversation that's on a user's Timeline page.

In January, we asked a small group of pinners to test a new look designed to make discovering things on Pinterest easier. Since then, we've talked to some of these folks, analyzed their feedback, and made a few changes. Today, we're thrilled to start sharing the new look with everyone.

There's an old English saying, "Keep a thing seven years, and you'll always find a use for it." Today is Twitter's 7th birthday, which we observe on the day @jack first tweeted. Since then, we've seen breathtaking velocity in Twitter's growth, which is due entirely to your many uses of it.

Smarter search. That's the promise from social networking web site LinkedIn with its revamped search capabilities. In a blog post announcing the new search tools, Johnathan Podemsky, who according to his LinkedIn profile is a product manager at LinkedIn, noted that 5.7 billion "professionally-oriented searches" were done on LinkedIn last year.