• by Mark Walsh  @markfwal, October 29, 2013

As Instagram begins to rollout photo and video advertising, a new study suggests video ads won’t necessarily take off on photo-sharing service. In the third quarter, video posts accounted for only 6% of all brand posts in the third quarter, according to the research by social analytics firm Simply Measured.

Overall, a growing number of companies are embracing Instagram as a marketing platform, with 71 of the world’s top 100 brands having a presence on the service, up from 40 a year ago. That level of adoption puts it roughly on part with Google+ and Pinterest and makes Instagram the fastest-growing social property among marketers

Among other key findings from the third quarter:

--As activity increases, so do followers. 57% of top brand marketers are now averaging at least one post per week, up from only 38 percent in Q3 of 2012. As a result, more than one third of top brands have 10,000 followers and 19% have audiences over 100,000 followers.

-Automotive, media and luxury brands dominate. Mercedes-Benz, BMW and Audi make up three of the top five most engaging brands. In total, the top ten brands received 83% of all Instagram engagement, while accounting for a third of all posts.

-Photos generate more engagement than videos. With video still slow to gain momentum, photos are driving 26% more likes and comments than videos. Instagram debuted its 15-second videos in June as a precursor to a paid video format launching now.

-Hashags have become the norm. 83%  of Instagram posts include at least one hashtag, with 63 of the 65 active brands on Instagram using the new feature. The Interbrand top 100 brands use hashtags more sparingly than other brands.