An app without stickiness is nothing. Someone downloads your app--woohoo!--they tinker around for a minute or two--yay!--and then they go back to Facebook.

What have you gained? Not a lot.

Without that je ne sais quoi that gets your users clicking into your app again and again, you're never going to have a strong product. And studies have shown that this is a very common problem. 20%, in fact, only get used once, and if an app is only opened one time in the span of a week, there's a 60% chance that it'll be the last time.

A smart growth hacker knows that she needs to find that moment or feature that turns curious clickers into devoted power users without breaking the bank. Fortunately, there's a lot of great, free tools out there to help do just that.

1. Cohort analytics

90 day cohort retention numbers, or the amount of users that are still using your product after three months, were cited by Fred Wilson of Union Square Ventures as the single most important thing for entrepreneurs to focus on when raising money. These numbers effectively tell you the long-term health of your business: if users are ditching your product in droves that soon, then you know that you don't have product-market fit, and that you're in trouble.

When Facebook analyzed what cohorts of users were most likely to stick around and become consistent, long-term users, they found that there was one especially reliable indicator: when users added 7 friends in 10 days. If they got to this "AHA" moment, they were engaged, and they stuck around. With a single focus in mind, the Facebook growth team was able to concentrate all of its efforts on getting other users to this moment.

Analytics tools can be very, very pricy however. Most providers charge by the event, which gets expensive as you grow and will dissuade many from even bothering to measure certain factors. Amplitude, on the other hand, has an extensive free plan that makes it easy and affordable to track just how sticky your app is for 10,000,000 events--something that you might be charged $10,000 for elsewhere. That means smart growth hackers everywhere can now look at way more of their data without being hamstrung by finances.

2. Personalize your email content

Consumers today are bombarded by more offers and promotions than you can shake a stick at. To cut through that noise with your product, it's critically important to craft the right messaging to send to your users. You need to show your users value, get them to see understand why your app is something they should be coming back to again and again, and show them how to use it.

A smart customer service pro gets in touch with their users right after they sign up, then again two days later, then four days later. Etcetera. They remind them that they're around, that they're paying attention, but they don't overdo it because they'll end up relegated to a spam folder.

They also make sure their messaging is personal--this is what ensures that their emails actually get opened instead of just being canned. One of the most powerful ways to do so is through Customer.io--it simplifies the process of managing your campaign, personalizing your messaging at scale and getting in touch with the right people.

3. Reliable financial metrics

It's a competitive market out there, and even SaaS companies need to be thinking about user engagement. A lack of stickiness in a SaaS product, when there are usually so many alternatives out there, can mean the beginnings of revenue churn. This is one of the issues most likely to sink a business. A tiny adjustment to your churn rate can have a huge, outsized influence on your revenue just because of how expensive it is to obtain new users.

Plus, financial metrics are complicated. Smart entrepreneurs often don't even realize they're calculating theirs wrong. Smart entrepreneurs also shouldn't spend too much of their $1000/hr time doing accounting tasks anyway, especially when a metrics-provider like ProfitWell will do it all for you for free.

Their metrics are delivered in the form of actionable analysis, which means you'll understand what your churn number is, what's caused any changes, and what you need to do about it.

4. Hack your processes

In The Checklist Manifesto, Atul Gawande shows how something as seemingly simple as checklists created a dramatic improvement in the level of care that doctors gave their patients. As highly educated and trained as these doctors were, checklists were still helpful because they compressed a lot of thought and process into an easy, actionable document.

The same principles apply to entrepreneurs: if you're going to start and grow a business, you need to turn your brilliant processes into something that's repeatable and therefore scalable. Process Street makes it simple for non-developers to create complex, repeatable checklists on which your team can collaborate and also share the amount of progress you've each made.

That means that on any given task, your engineers, designers and marketers can all see just how far along everyone else is, and make adjustments as necessary. Reducing your product's churn is a process you need to take seriously, and putting in the effort to make actionable checklists to organize that process is the best way to make sure it actually gets done.

5. Build personalized notifications

Push notifications come in many shapes and sizes. Sometimes they can be effective, and can remind people of your value proposition, and keep users coming back again and again. But these kinds of notifications aren't the ones that people notice: people notice the annoying ones, the ones that seem to come out of nowhere, are totally irrelevant, and quickly result in the revoking of notification privileges for the offending app.

Leanplum is a service that lets you personalize the notifications you send based on some activity a user has taken inside the app, the demographic you're trying to target, or a geographic location. Push notifications are, of course, not ideal. You haven't yet managed to turn your app into something that people organically return to. The key to success with push notifications is bringing users back into your app who are going to themselves attract other users, setting off a cycle of retention that you can use push notifications to maintain.

6. Improve your site's effectiveness

The very top of your site, because of the way that humans interact with the web, is going to be one of the first and most prominent things that users see when they visit. That's valuable screen real estate, and if you're smart, you'll want to get as much out of it as you can.

Hello Bar is a simple plugin devised by Neil Patel that creates a flexible, easy-to-use bar right at the top of your site. With it, you can do any number of things: drive visitors to the page they should visit next, advertise your email list and give users ways to promote your content. There's also inbuilt A/B testing, so that you can see which iterations of your Hello Bar work best for the people who are visiting your site.

7. Find your promoters

When American Express started experimenting with Net Promoter Score surveys, they found something surprising that helped them re-align all their efforts to improve retention. Those respondents who answered with a 9 or a 10 (meaning it was very likely that they would recommend American Express to others) were four times more likely to stick around, and they also spent 10-15% more than other customers.

All customers are not made equal, as that NPS survey made clear. These are awesome tools, but running one can be time-consuming, which is why a service like Promoter.io is valuable. With Promoter.io, you just specify the timing of the emails, and they do the rest. With the results organized and collated according to how satisfied your customers are, you have all the data you need right at your fingertips.

8. Integrate your data and tools

If you're a smart growth hacker, you're collecting a lot of data. You're using that data to automate your marketing and you're looking at your analytics to learn more about what works. But as far as we've come with these individual tools, it can still be time-consuming and frustrating to get all that data from your mobile app, site and servers to the various tools you're using. Plus, there's really no easy way to give different services a spin and see what suits you best.

Moving your data around into Amplitude, and Customer.io, and Intercom, and Promoter.io--this can get annoying. Segment will do the heavy lifting for you so you can focus on actually using that information instead of figuring out how to make it visible. All you have to do is drop the code in once, and immediately integrate with over a hundred different tools. If you've already incorporated your data into apps, then Segment even lets you take that old data and replay it into the new apps of your choice.

9. Engage through downtime

Another thing that can just crush your startup is downtime. One of the reasons that Facebook was able to leave Friendster and MySpace in its dust was that Facebook didn't go down very often: Friendster, on the other hand, suffered outages that would last days and when it came back, it was always slow, bordering on unusable.

For a site or app to be truly sticky, it needs to operate frictionlessly and at high speed. Google, Facebook and Youtube have, after all, gotten the internet-going public very accustomed to near instantaneous information retrieval. You need to be able to match up.

StatusPage helps by providing a safety net in case something does happen, as it probably will. Smart growth hackers know why their site is down, but they don't always realize that all the outside world is seeing is a 404 or a fail whale. All those people are going to assume is that 1) your site is down, and 2) it sucks. StatusPage helps your customers understand that rather than being dead or hacked, you're just in a temporary state of maintenance or downtime.

It might seem trivial now, but staying in touch in this way is actually really meaningful and helpful not just to your users but internally as well. This way, when you're onboarding engineers for instance, you can assure your new hires that execs won't be stomping around the office searching for an explanation for why the site is down.

10. Interactive in-app conversations

Making sure your help desk/support experience really shines is key to keeping customers around as you grow. There's probably not a company in history that's managed to scale without experiencing at least some issues, and when those issues crop up, you need to make sure that someone is around to talk to your users about it.

This is how shred business owners approach things: when you walk in their store, they'll ask you how you are, listen if you think something is wrongly priced, just try to get to know you. A lot of otherwise intelligent entrepeneurs don't even realize how far they've strayed from this time-tested model. They can barely tell who their regular users are.

Your customer success and design teams, in particular, need to be talking to users all the time, in fact. They should take any chance they can get to find out more about the people on their site, and Intercom works well for this, with detailed info on who's using your site and a powerful in-app messaging system.

11. Understand the user experience

Smart product managers and designers understand that they're cursed by their own knowledge. When you put together a site and present it to the world, you are the only one that truly understands how it's supposed to work. Your users, even though they're the most important element, don't. That's why it's so important to get stuff out there fast and see how users respond.

To truly incorporate the end user's needs, you need to see how they actually interact with your site. Full Story lets you record, replay and analyze those experiences that your users are going through. If you have customers who haven't come back in a while, you can check out what their last session looked like. You can see what prompts people to start inviting their friends to your service. Or you can look specifically at how your mobile checkout process is working for first-time customers.

12. Build a smart onboarding flow

One of the most critical touch points for your customers is your onboarding flow. Since users who don't return to your site after trying it once are such a large generator of churn, you need to optimize that process with a fine-toothed comb and figure out how to make it perfect.

After all, as smart as you are, your first-time users are coming into your site with far less understanding of how to use your features. Chances are, if they can't find something they're looking for right away, they're off to your competitors. Plus, the way you're going to build retention into your product is by making sure that your users can seek out and find the value proposition they need as quickly as possible.

Appcues makes it easy for non-developers to build personalized onboarding flows with a wide variety of templates including fullscreen takeovers and in-app alerts, A/B testing and extensively customizable messaging. The first thing most of your users interact with should be a tutorial. Then, depending on the actions they take on the site and their intentions, you can trigger any number of subsequent events, from tooltips to emails to in-app messages.

No more leaky buckets

A smart growth hacker knows that their site or app's stickiness is the thing that glues growth and retention together. Both of them are incredibly important, and neither of them can exist without the other. Scaling them both up means spending time figuring out what your product needs to be so you can get more users and induce your existing ones to keep coming back.