PR Shutterbugs: 10 Must-Follow Brands on Instagram 

Once considered a fringe social network for only the most creative and daring brands, Instagram, the mobile photo-sharing platform, attracted an average of 7.3 million daily users in the U.S. via mobile devices in August 2012, surpassing the 6.9 million who visited Twitter via mobile devices, according to data from comScore Mobile Metrix 2.0.

Consumer brands, nonprofits and news outlets alike are using Instagram to snap photos, apply Polaroid-like filters, captions and hashtags and posting their creations on Facebook, Twitter, Tumblr and other popular social networks.

Here, we've compiled an alphabetical list of 10 must-follow Instagram brands—both for your personal enjoyment and for generating some ideas of your own on using Instagram for your own brand. 

• @charitywater: Nonprofit charity: water brings clean and safe drinking water to people in developing nations, and 100% of donation go to funding water projects. The account shows its grassroots efforts around the world and beautiful imagery of water and its role in developing countries.   

• @generalelectric: General Electric doesn't exactly come to mind as a sexy and creative brand to follow on Instagram, but GE provides unique photos of its complex range of technologies. GE held an Instagram contest and nearly 4,000 Instagram photos were submitted with the designated hashtag#GEInspiredMe. They were then posted to Facebook, where fans voted for the finalists. The winner was shipped to Wales to photograph a GE aviation facility. YouTube and Facebook—as well as a GE Pinterest board that showcased all the submitted #GEInspiredME photos—helped extend the contest's reach.

• @levis: Levi's uses Instagram to highlight its rich brand history, showcase the product's cultural significance and how everyday people and celebrities alike live their lives alongside the iconic brand. To crowdsource the next hot talent to appear in Levi's advertising in 2012, the fashion brand asked fans to upload their images on Instagram, using the special tag #iamlevis.

• @nbcnews: NBC News is using Instagram to tell its own stories, and user-submitted photos to add another dimension to its news reporting. The account is used by NBC reporters for on-the-scene reporting from the campaign trail, as well as user-based hashtag collections, the latest of which asks Instagram users to share the autumn's colorful leaves in their area with the hashtag #HC_FallFolliage.

• @nycmayorsoffice: The account of New York City Mayor Michael Bloomberg is used to highlight NYC's landmarks and its residents, as well as some of the mayor's day-to-day activities. Regardless of your political alignment, this account provides followers with beautiful behind-the-scenes views of NYC that few have access to like Mayor Mike does.  

• @prnews:Sure, we may be biased, but we think our own Instagram account features a healthy blend of behind-the-scenes conference happenings and staff photos, as well as light-hearted and inspirational quotes about working in the PR industry. Followers can also look forward to additional Instagram contests leading up to our conferences and events. See you on Instagram.  

• @redbull: Red Bull has amassed over 415,000 followers by tapping into the action sports culture that exists around its products. The brand also capitalized on something near and dear to most everyone's hearts: summer. Its #summeriscoming contest ran during the summer of 2012, and on each Monday Red Bull chose a new theme for fans to use in their photos. Red Bull didn't ask users to photograph its products, they simply asked for each photo to be tagged with that week's theme (#summerishere, for example) and @Redbull. The accounts with the most submitted photos then had the best chance of winning each week.

• @refinery29: This fashion, beauty and shopping website's Instagram account stays true to its profile description: "Follow us for exclusive, eye-popping images you won't find anywhere else." The brand has also hosted several contests on Instagram. For summer 2012, Refinery29 partnered with Smashbox cosmetics to ask fashion and music fans to capture their favorite concert moment and tag it with #festivalsmashbox on Instagram. The winner received a $5,000 VIP package for a trip to a 2013 music festival and a suite of Smashbox products.

• @starbucks: Starbucks plays into the emotional connections the coffee brand has built with customers through every cup of coffee sold and tries to recreate the experience of enjoying a cup of Starbucks. An early adopter of Instagram, Starbucks highlights in-store experiences at locations from around the world, as well as new seasonal items. Following Starbucks is an instant pick-me-up for Instagram users. 

• @warbyparker: Warby Parker has taken its love for Instagram from the small (mobile) screen to real life. The glasses brand staged a handful of unpaid “Instawalks,” inviting fans of the brand to walk around New York City while taking photos. It loaned frames of its glasses to attendees at the start of the events and asked them share photos of them with followers through SoHo,  the West Village, the High Line and at rooftop of the Gansevoort for Warby Parker-themed cocktails and a view of Manhattan at sunset. It's estimated that the event generated about 850 photos and reached a total audience of some 370,000 Instagram users, reports AdWeek.

Know any other must-follow Instagram accounts that can help other PR pros percolate ideas for their own efforts? Let us know in the comments section. 

Follow Bill Miltenberg on Twitter: @bmiltenberg