Facebook has put in an offer to buy Instagram, the popular photo-sharing site, for $1bn.

"I'm excited to share the news that we've agreed to acquire Instagram and that their talented team will be joining Facebook," said Mark Zuckerberg, Facebook CEO, on the Facebook blog on the shock announcement on Easter Monday.

The deal, which is subject to the usual authority approvals in the US, shouldn't affect Instagram's independence, according to Zuckerberg:

"We believe these are different experiences that complement each other. But in order to do this well, we need to be mindful about keeping and building on Instagram's strengths and features rather than just trying to integrate everything into Facebook."

It is a message mirrored by the founders of Instagram, with co-founder Kevin Systrom, writing on their own blog: "The Instagram app will still be the same one you know and love. You’ll still have all the same people you follow and that follow you.

"You’ll still be able to share to other social networks. And you’ll still have all the other features that make the app so fun and unique."   

The deal will give Facebook a massive boost in the photo social stakes.

"For years, we've focused on building the best experience for sharing photos with your friends and family. Now, we'll be able to work even more closely with the Instagram team to also offer the best experiences for sharing beautiful mobile photos with people based on your interests," said Zuckerberg.

"We think the fact that Instagram is connected to other services beyond Facebook is an important part of the experience. We plan on keeping features like the ability to post to other social networks, the ability to not share your Instagrams on Facebook if you want, and the ability to have followers and follow people separately from your friends on Facebook."

The Facebook CEO was keen to lay praise on the 17-month-old company:

"We will try to learn from Instagram's experience to build similar features into our other products. At the same time, we will try to help Instagram continue to grow by using Facebook's strong engineering team and infrastructure."

With Facebook's focus on photos, Timelines, and being part of your life whatever part of "social" that is, the move by the company before IPO in June makes a lot more sense. Facebook already captures some 250 million  photos a day, and with the addition of Instagram's 27 million users that number is going to grow. 

What also makes sense is Zuckerberg's praise for the company. His social network paid double the market value for the photo-focused site with iPhone and Android app support. Last week, Instagram took $50m of funding, valuing the company at $500m.

The move also no doubt helps Facebook justify its expected $1bn valuation. After all, if it paid $1bn for Instagram it has got to be worth 100 times that, hasn't it?

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