Although there are several major players in the social app space, Yo has attracted brands much more quickly than Facebook and Twitter. Since brands are paying more attention to the mobile space for marketing growth, they can tend to overthink their strategy, but Yo allows them to keep the delivery of content simple.

?I'm completely blown away at why the Yo app has taken the market by storm,? said Sheryl Kingstone, director at Yankee Group, Toronto. ?I can understand, however, why retailers and brands will jump on board. 

?It's not like it does anything that?s remarkably different than Twitter or even any push notification service,? she said. ?However, it gives the potential to easily communicate with customers if we can ensure the information we are receiving is relevant and not spam-like. 

Brands to join the messaging app have been far and wide, including Los Angeles Times, NBA, Showtime, HuffPost Dinner, Mashable, Buzzfeed, Sony Pictures, CBS Sports and more.

?This is a really interesting app,? said Sandhya Suryam, marketing director at Atimi Software, Vancouver. ?It has a simple UI/UX, there is a great tutorial to get you started, and the simplicity of concept seems to lend to user adoption. 

?Like any new social media tool, the end user is dependent on their network of friends jumping on board with them, but the ease to invite your contacts should help facilitate that.? she said. ?It definitely lends well to millennials? use.

?It?s interesting to see that NBA, GE, and USA Today have already started to use the platform to engage with users. Their early support, being trailblazing brands on the app, will establish a foothold and generate more awareness about the app.?

USA Today used Yo to deliver updates from the election in November. Given Yo?s core audience tends to be a younger demographic, USA Today tested this platform to educate Yo users about the election and make the content more digestible (see story).

Yo users can also now receive notifications about opportunities to win free tickets to concerts from iHeartRadio thanks to a new partnership between the two companies (see story).

?There is a feature that allows bloggers to send a Yo to their followers when they have a new post out,? Ms. Suryam said. ?There is a lot of potential for a brand to use a feature like this to ping their consumers, let them know about a sale or something else of interest on their Web site, alert them to new items in their stores, or a retailer could Yo consumers with a location of a flash sale or warehouse sale. 

?It?s a quick interaction with the consumer with seemingly low effort,? she said.

These brands use Yo to deliver content in its own form of a push notification. When a Yo is received, users can click on the notification and read the content that has been delivered. 

?I will be a huge advocate of any successful push notification message that adds value into the customer experience such as knowing my table is ready or a particular item is on sale,? Ms. Kingstone said. ?Fundamentally, do you need Yo to do that? Not really. That's why I am so surprised. 

?Can it become a big player? Yes,? she said. ?I can see a widespread adoption of anything that goes viral. 

?However, that does not mean it can maintain the success. Yo competes more with SMS messaging and Twitter than Instagram.?

Yo works because of its simplicity. Often times, mobile is overthought, and campaigns are too complex for users to adopt. 

For consumers, Yo is an easy way to reach out to other users about nothing in particular. For brands, the interaction is similar. Users that subscribe to brands? content on Yo are dedicated enough to them to desire regular updates.

?It will be worth watching Yo to see what the adoption rate is,? Ms. Suryam said. ?All new social media platforms do need a critical mass to be successful. 

?Early adopters can help give the app some traction,? she said. ?Brands using their marketing dollars to let consumers know they are on Yo will also help the app gain awareness. 

?I think it?s a bit too early to say if it can compete with Snapchat and Instagram, especially as there are many parody or like-minded apps following Yo?s example. One of these similar apps might gain better traction.?

For Yo to continue on an upward stretch, the content must remain relevant and wholesome and must avoid spam, a big issue that email marketing constantly faces.

Email marketing can sometimes deter users. In fact, mobile email opens appear to be plateauing with less than half of emails opened on a mobile device in November, down from last year when the rate topped 50 percent, according to new data from Return Path (see story). 

When marketers contact consumers too often or with irrelevant information, they are more likely to unsubscribe or stop opening emails. The Yo app works similarly to email marketing and push notifications, so brands that are investing time in the app must be cautious.

?It's so fundamentally simple that it boggles my mind that it's gone viral so fast,? Ms. Kingstone said. ?I just hope that it's used effectively and not turned into some spam engine. 

?If that's the case, we will ignore all Yo's in the future,? she said.