Every morning , Dirk Dallas takes a trip around the world . With his own eyes , he studies artful , real-time images of life in New York , Paris and Hong Kong . But Dallas , a graphic designer , does n't actually leave his Riverside , California , neighborhood , or even his front door . He just needs his phone and a digital portal called Instagram . `` It 's like taking a vacation every day , '' said Dallas . `` Instagram is different than any other social network I 've been on . '' The freedom to share and connect with users across the globe is big part of what keeps Dallas coming back to Instagram , the wildly popular mobile photo sharing app , again and again . It 's that same appeal , Dallas figures , which led to Facebook 's stunning purchase of Instagram this week -- the single largest acquisition in that social network 's 8-year history . `` Facebook is n't buying an app ; they are buying us , '' said Dallas . `` They are buying a community . '' Facebook turned the tech world on its head Monday when the social media giant laid down a whopping $ 1 billion in cash and stock options to gobble up Instagram , a scrappy , San Francisco-based startup with just 13 suddenly very rich employees . Instagram has seen explosive growth , racking up more than 35 million registered downloads in just 18 months . Its community doubled in size the last five months alone -- turbocharged in part by the release of its long-awaited Android version last week -- which propelled a million new users to sign up in the first 24 hours . On Tuesday , propelled by a wave of publicity , the free app hit the # 1 spot on Apple 's App Store for the first time ever . The billion-dollar question still looms , of course : Why would the world 's largest photo-sharing platform fork over so much money for a tiny company that was evaluated at half that price ? Business analysts and tech geeks have speculated on the motives , but the heart of answer just might lie in the passion of Instagram 's most invested users . At its core , Instagram is a remarkably simple way to share mobile photos . Users snap pictures , enhance them with filters that add an arty or vintage look , and share them with their followers . As on Twitter , users can follow other Instagrammers , whose photos then show up in their streams . Users can `` like '' or comment on photos , as they can on Facebook . Tyson Wheatley : My year through the lens of a really smart phone . But to many of its most loyal users , Instagram is much more -- a creative outlet , a place to be inspired every day and a platform to make new friends . `` Instagram has changed my life , '' said Bex Finch , who has more than 100,000 followers on the network . `` I love being able to share my world with people I do n't know but [ who ] inspire me . '' But Finch , a San Francisco-based photographer who says she has landed gigs by connecting with clients via the app , is worried a massive influx of new Facebook users could spell the end of Instagam 's charm . `` Maybe Instagram has played its role , '' she said . `` Maybe it 's time to move on . '' The blogosphere in recent days has been full of similar complaints from Instagram users worried that Facebook will sell their personal data or pollute their photo streams with ads . Photographer Benjamin Heath is more cautiously optimistic . `` Let 's wait and see what happens before we pass judgment , '' said Heath , who also lives in San Francisco . `` Of course I would be very angry if Instagram became something I no longer want to use , '' he said . `` But there 's no reason to suspect that yet . '' Heath believes there could be a silver lining as the service skyrockets in popularity : improved features such as adjustable filters , perhaps , or an easier way to keep track of talented users . With more than 800 million users , Facebook knows a little something about scale . And Instagram 's rapid growth has created its own bumps along the way . Early adopters have complained that Instagram 's `` popular page '' has become nearly impossible to reach and is often filled with photos that people did not take themselves -- too many semi-clothed teens , for example , or Justin Bieber tributes . Longtime Instagrammers gripe that some users are there merely to gain followers , not necessarily to join what Shah Kashani describes as a `` thriving community of like-minded people thirsty for photography . '' `` I 'm just as much a viewer as I am a photographer , '' said Kashani , a web developer from Brooklyn , New York . `` And that 's the same with everyone , so there 's this constant feedback loop . It almost feels like this collaboration in becoming better photographers . '' Kashani wants to keep his Facebook and Instagram accounts , and communities , separate . `` The problem with my Facebook is it 's all over the place , '' Kashani said . `` I 'm connected to colleagues , family , and friends , but I feel like I 'm forcing my photography on Facebook . '' Serge Najjar , a lawyer in Beirut , does n't have a Facebook account . Nor does he want anything to do with it . `` It 's always a new challenge to put up with change , '' Najjar said . `` What I fear is Instagram losing its simple approach . It 's a very pure , social , exchange between people who share the same passion . '' Dallas , the Riverside Instagrammer , also is concerned about Facebook 's vast reach . `` Instagram is a very small team . They are nimble and fast and can make decisions , '' he said . `` My fear is that now there will be more layers to this creative process . '' Ike Edeani , a graphic designer in San Francisco , bought his first iPhone partly so he could download Instagram . He admits he can easily spend four hours a day interacting with the app 's visual community . `` I do n't really get excited about posting photos to Facebook , '' Edeani said . `` But that 's exactly how I feel when posting to Instagram . '' Edeani says that by treating his phone like a camera , he is more open to exploration . `` Instagram reawakened my creativity in a lot of ways , '' he said . `` I 've learned to react to that spark -- when I see something just walking around -- and not just dismiss it . Here is this little app that 's connecting us all [ in San Francisco ] and inspiring us to go out and explore this city we live in , to wake up at six in the morning to go capture a sunrise . '' Edeani said he 's not considering quitting Instagram at this point , in part , because `` there 's noting else out there compares . '' Not everyone agrees . Some Instagram users have already made the jump to other platforms . Robert-Paul Jansen , a web developer living in The Netherlands , said the Facebook deal was the `` final push . '' He closed his account Monday , leaving behind more than 2,000 followers , and now shares his mobile landscape photography on EyeEm , a Berlin-based competitor to Instagram . Jansen is not the only respected Instagrammer to flee the app this week . But fears of an exodus , for now , appear greatly exaggerated . Still , even the most optimistic Instagram users are left with wounds . `` What happens the next time a tool is created that taps in to my interests ? '' wondered Heath . `` Am I going to feel the same way ? Or can we assume that all great things will eventually be owned by Facebook , Google , Amazon , Apple , or Microsoft ? '' Whatever the motives for the deal , few users seem to be holding CEO Kevin Systrom and the rest of the Instagram team in contempt for selling out . In the end it 's a billion dollars , '' said Heath . `` I do n't blame [ Instagram ] . There 's no black and white . It 's just a lot of bread . ''
Facebook bought photo sharing app Instagram for $ 1 billion on Monday . Comment: But many users worry that Facebook will kill what 's wonderful about the app .