As for “viral coefficient”, I was meaning to comment on that. What is the main difference between the old-school “churn rate” and “viral coefficient”? I prefer the Old English churn versus the Latin viral. OK, that was an English nerd moment there.

@Will Nourse: Is the problem of Facebook a signal/noise problem or is the problem a lack of organic site traffic on an originating nonprofit’s site that leads to inactivity on Causes? I think we’re still in holding mode waiting for more data on this. My guess is that if Justgiving can target a Facebook app just for its users, it might just be possible for nonprofits with lots of online traffic to do the same thing. Looking at it so far, it seems that Team in Training-type campaigns could benefit from a Facebook app as that seems to fit the same kind of demographic that Justgiving targeted with its app.

1. Do you have a ceiling in your projections where you think the churn rate and the add rate will cancel each other out?
2. Did you optimize your Google Analytics to work with your Facebook app? Is that even possible?
3. How did you survey your users regarding user satisfaction?
4. What business factors led to the creation of the justgiving app?
5. Do you have a list of key performance indicators for the app?

Plenty more after those but I didn’t want to inundate you with an avalanche of questions.

Firstly, thanks for featuring us, it’s nice to be written about and great that the app has been noticed!

Growth has been steady since launch last summer (about a month or so after the FB app platform launched itself). Last time we checked the installs were at about 75,000 and the usage rate varies between 5-10%, which is pretty cool considering the app itself was designed to be purely functional and not sexy. It’s only got a donate button on it, after all.

We have had a very large userbase for years now, so when we launched it was merely a case of letting our fundraising users know, and within hours we had hundreds of installs. So you’re bang-on; having plenty of site traffic to send through to the app page has really helped grow those numbers.

We’re not as much interested in spread of the *app*, but more about spread of our brand within FB, and getting across the concept you can use it to fundraise for anything. Most of our referral traffic is coming from FB’s internal messaging system, wall-posts, groups and event pages. The app itself is responsible for about 10% of our FB referral traffic.

It’s also worth noting that now, unsurprisingly, FB is our single biggest referrer, knocking Google off its perch earlier this year. Each month the gap between the two widens.

My take on it is that our users are just looking for easier ways to ask their friends for donations, and Facebook is the least awkward way of doing so. The app plays a small part of that, but our focus is not only displaying which causes you support, but more about actually raising more money than thought possible. The dollar value of our Facebook referrals is huge.

The way Facebook has split an individual’s social graph wide open has real synergy with this concept, and has made much more of an impact than email and non-platform-specific flash widgets (which we have too).

I’m not expecting a *huge* summer dip in activity because the London Marathon is by no means our only big event of the year. However there is always a seasonal dip in P2P fundraising but we’re not forecasting it to tail off. I still don’t think it’s hit the full potential yet since many of our users of older demographics are only just discovering Facebook. Also, it’s wedding season and we get tons of wedding list pages asking for donations instead of shiny toasters.

We’re now focusing on the potential impact of the forthcoming profile changes. Apps are cool but they’re just part of our user’s arsenal and as Ben points out, it’s the viral efficiency within the whole system that counts.

Totally happy to answer any questions you might have, we’ve got tons of internal analytics data on this, as well as qual data on how people actually *want* this stuff to work.

Ultimately, if I were to boil down what you wrote into a rough rule of thumb, it would be:

You have to have enough site traffic to drive Facebook traffic to your app.

I’m really curious as to what the summer will bring for the Justgiving app.

But virality is easier said than done, and for most useful apps in which inviting friends is not an inherent part of using the app, it’s very difficult to get a viral coefficient of greater than 1, which is the only real way to get distribution inside Facebook. (As I described in more detail in the post you referenced.)

The case of FirstGiving is interesting, but my guess is that their growth is not happening organically from inside Facebook but rather because users of their main site are being pushed to add the app inside Facebook. Actually, that is almost certainly the case, since it is mathematically impossible for them to be growing any other way inside Facebook unless they have a viral coefficient of greater than 1, and if they had that, they’d likely be growing much more rapidly.

On general Facebook apps, I think the issue of signal to noise is a critical one – it’s one reason we’re not putting a big premium on Causes as a vehicle for engagement.