Liputan Sosmed

When Facebook bought Instagram for $1 billion in April 2012, the price tag came as a shock to many. A little more than two years later, Citigroup said Instagram is worth $35 billion, a number that the bank called "conservative" in a research note on Facebook issued Friday.

It is another piece of good news in what has been a stellar 2014 for Instagram. The photo-sharing app recently hit 300 million active users, putting it ahead of Twitter. At $35 billion, Instagram would also be worth more than Twitter, which currently has a market cap around $23.3 billion.

Citi's analysts added, however, that the valuation is speculative and dependent on efforts to generate more money from the app.

"While Instagram is still early in monetizing its audience and data assets, and its financial contribution to [Facebook] is minimal today, we believe that it is quickly gaining monetization traction, and would contribute more than $2bn in high-margin revenue at current user and engagement levels if fully monetized," Citi analysts wrote in the note.

Facebook has not been in a rush to fully monetize Instagram, rolling out its first ads in late 2013, and recently adding video ads. While Facebook has not disclosed how much money Instagram is generating, Citi's analysts said it could conceivably bring in $2.7 billion in 2015.

A Forrester Research study found that users are far more engaged on Instagram than other social networks, such as Facebook and Twitter. Facebook has become a particularly frustrating platform for marketers, as the site has scaled back how much reach brands can have on the site's News Feed [Mashable].

Hiding photos on Facebook may not actually work as well as you think it does. Picturebook, a browser extension now available in the Chrome web store, claims to allow you to "view hidden photos of anyone on Facebook"— even if you aren't friends with them.

Sounds like a Facebook creeper's dream, right? But though Picturebook's description is technically true, it is also misleading. No app or browser extension — this one included — is able to change the privacy settings of someone else's photo. What Picturebook is really doing: surfacing photos that you could have seen anyway, even if a user tagged in them hid them from their timeline.

Say a friend tags you in an unflattering photo. You can make it go away by selecting "hide from my timeline." But this only prevents people from viewing the photo within your timeline; it doesn't actually remove or block the photo in any way. If the photo's privacy setting was set to "public", anyone could have found it anyway.

Other users will still be able to see the photo by visiting your friend's timeline, or simply by searching for it.Picturebook takes advantage of this loophole and surfaces photos you've been tagged in, regardless of whether you've hidden them.

In short, Picturebook makes it just a little easier to find what you could have found anyway. It's worth pointing out that Facebook reminds users every time they hide a photo that it is still viewable from others' news feed, from search, and from other places on Facebook.

The only way to really hide your hidden photos from this tool is by untagging yourself. First, select "hidden from timeline" from the drop down menu under the photo's date. From there, select "Report/remove tag" from the popup window that appears, then select "remove tag."

This removes the tag, which will prevent photos from appearing on your timeline, or on the Picturebook extension. The photo itself will still appear elsewhere on Facebook; only the person who posted it can remove it.

If you're still worried about old photos showing up, now may be a good time to revisit your privacy settings, to make sure you're only sharing what you want. The social network recently made privacy settings more accessible with a new Privacy Basics page, intended to make this process easier [Mashable].