Social-media app Vero arrived with a splash this past week, hitting No. 1 on the Apple and Android stores, grabbing 3 million subscribers before spawning an online backlash. Not bad for an "authentic" social-media app that first launched three years ago.More interesting, however, might be what lessons others can take from Vero's rise and stumbles, in terms of building the next good app that can give users what they want while making money in a sustainable way.Though Vero's sudden rise mystified most observers, there are some solid suspicions about what worked.To begin with,  Vero looked pretty good to users seeking alternatives to the tech giants after many months of controversies, boycotts, interface and algorithm changes, missteps and mayhem. Vero's initial modest success came from cosplayers, who liked that it offered photography capabilities that Instagram doesn't.Others liked Vero's use of a chronological ordering of posts in user feeds. Creators, particularly on Instagram, have been frustrated with its recent shift to an algorithm that decides what posts users see. The creators blame the algorithm for a big drop in user engagement.Another nice feature allows users to designate each follower as "close friend," "friend," or "acquaintance," and to control what content gets seen by each. That's a nice modulation between Facebook's default Show Everything mode and Snapchat's default Zap Everything mode.Like Instagram, Vero posts can be shared onto other platforms, in this case Facebook or Twitter The various media and links you share get saved and organized into "collections." And of course it does messaging, as even Instagram now allows.Vero has promised it won't show ads, and has put on hold its plan to charge a modest subscription fee of  "several dollars a year" once it passed 1 million users "until further notice." That combination of features all suddenly looked good to potential users, and once a certain critical mass was hit, the app took off. Vero, which means "truth" in the constructed language Esperanto, hit No. 1 in both the Apple and Android app stores, something that's damned difficult for a three-year-old app without a mighty marketing push.But after the big rush, many new users had second thoughts. First of all, the app continues to get rated at around 2 stars. It's not a particularly attractive app (one outlet called it the ugliest social-media app out there), and worse, the sudden crush of interest has overwhelmed Vero's functionality, making even simple signup difficult.The app's terms of service claim an expansive list of irrevocable rights to each user's content. As scary as the list is, it's important to note the language is nearly identical to that found in the service terms of other major social-media sites. Nonetheless, it became another black mark for those with sudden concerns about the company.Even worse, some users were upset to learn about some of the business background behind the app's backer, billionaire Ayman Hariri, son of an assassinated former Lebanese prime minister.Hariri has ties to a troubled family-owned company, Saudi Oger, which shut down after a cancelled Saudi Arabian construction project drew 31,000 complaints for non-payment of wages. Thousands of Filipino workers were marooned in labor camps with limited access to food and water. Hariri provided journalists with documents showing that he had divested from the company in 2014, before the project's troubles, but again, it became a black mark for some.Then came the next bad thing, difficulties deleting the app for those who wanted out. You can't just click a button on your phone to veto Vero. Instead, you have to submit a request to the site, and your account may not get deleted for some time, possibly because its employees are overwhelmed.So what are the lessons here for those wanting to build their own social-media powerhouse:

1. Subscription models, rather than ads, might be the way to go as the Internet matures. Ad models are getting pounded by blocking software, and users clearly don't like many of the design tricks employed to get ads seen. Are people becoming ready for subscription social-media services that aren't mining their life for ad revenue?
2. Good user interfaces and design matter. Vero attracted some users with interface improvements that Instagram doesn't provide, and avoided using algorithms that some users despise.
3. Make it easy to create nuanced relationship filters, and better track and organize all that you've posted. If you're active online, as most GenX and Millennial types are, being able to control The Who and The What matters a lot.
4. Make sharing easy in other ways too, even to other platforms, so your app can ride on the power of existing networks.
5. Invest in the scalable resources, such as servers, that you'll need if your app goes viral. Too few companies plan for wild success. That makes it difficult to take advantage should wild success actually arrive.
6. Spend time with your lawyers creating plain-language terms of service that give you flexibility without scaring potential users. You don't need the bad publicity.
7. Make it easy for people to leave. Again, you don't need bad publicity over a crummy opt-out process. Reduce the risk for trying out your app and more will do so.
8. Values count a lot for Millennials and GenX audiences, even when deciding what technology  and companies they want to use. Smart companies are picking their partners and backers carefully.

Vero may not be the blueprint for social media's future. But its quick careen along the story arc of  online phenomenology provides plenty of signposts to follow for those building that next great social-media app.