1.流失[Churn]
每个月离开游戏的用户量，有时候也选择用每周来衡量。举个例子，比如一款游戏在月初有100人在游戏，其中70个人在那个月结束后仍旧留在游戏中，那么我们就说流失率为30%，因为那个月中30个人从最初的100人中离开了游戏。
流失率也被用来分析一个玩家离开游戏的可能性。比如，一个游戏100个用户，其中30%的用户离开[30%流失率]。那么就意味着离开的可能性为30%，同样换个角度，也意味着，留下来的可能性为70%。所以如果我们要计算那个月结束后有多少玩家仍旧留在游戏中，那么我们就可以这样计算：留下来的百分比*月初的用户量，即70%*100=70，也就是说，该月结束时，有70个玩家留下来继续游戏。
如果我们计算两个月后，有多少人还留在游戏中，我们可以这么计算：70%*70%*100=49人，就是乘以两次留下来的百分比，进而计算两个月后仍有多少人在游戏。
把流失率作为一种流失可能性对待，能够帮助我们估计平均一个用户在游戏中生命周期长度。等式如下：
1/% churn =Ave.player LifeTime
举个例子，我们的月流失率为30%，那么我们的用户生命周期长度为：
1/30%=3.3 month
这点对于我们而言很重要，尤其是我们要计算平均每个用户对于我们的价值量时，这里后续会提到一个LTV（用户生命周期价值）。
如果我们忽略一个社交游戏或者其他游戏第一周的流失率，我们会发现周与周的流失率一直在5%到15%之间。每周5%的流失率对应每个月大概20%的月流失，每周15%的流失对应每个月50%的流失率。
2.平均每付费用户的收益[ARPPU]
平均每付费用户的收益，这个一般是按照月来计算的。换句话说，平均每个玩家花费了多少钱（注：大多数玩家是不花钱的，ARPPU仅仅计算那部分花钱的用户情况）。计算如下：
月总收入/月付费用户数
通常这是存在一些标杆的比如
- Virtual World: Habbo Hotel: $30 ARPPU (Sulake)
- Online Game: Puzzle Pirates, Three Rings: $50 ARPPU (Gamasutra)
- Social Game: Playdom: $20 ARPPU (Lightspeed Venture Partners)
3.平均每活跃用户收益[ARPU]
平均每活跃用户收益，如同ARPPU一样，这个也是每个月计算一次，ARPU的计算如下：
月总收入/月独立用户（月活跃用户）
依据账户方法论，这个指标能够告诉你从来自于衣服类道具购买的收入，该如何在用户生命周期中被均摊，同样的比如消耗性的，能量性（红、蓝药）的道具也能立刻通过此加以认识。但我认为这有一点小复杂。
Zynga的财报中我们看到他们每个月的ARPU大概是$0.40，当然这是他们全部游戏的一个计算值，实际上不同类型游戏的表现比另一些货币化的更好。
- Casual Social Game: A casual game is designed for anyone, including those without prior gaming experience. Such as Farmville, Cityville, Bejeweled, Words with Friends. ARPU around $0.10 – $0.20
- Virtual Currency Poker and Casino Games: Traditional gambling games that only allow players to play with virtual currency, such as Zynga Poker, Slotomania. ARPU around $0.25 – $1.25
- Mid-core Social Game: Typically more investment is required to succeed. Tends to be more competitive in nature, and players can be punished for not playing well, such as Mafia Wars and Backyard Monsters. ARPU: $0.25 – $1.25
- Virtual Worlds: Online worlds where players create avatars and interact in realtime, such as Habbo Hotel, Club Penguin, Runescape, and Puzzle Pirates. ARPU around $0.84 – $1.62
4.生命周期价值[LTV]
生命周期价值指的是平均每个玩家的消费金额。LTV包括了付费与非付费玩家。LTV计算如下：
ARPU*玩家留存游戏中的平均月的数量[玩家登录游戏平均月数量即 平均生命周期]
比如，如果我们的ARPU=$0.5，玩家总计在有5个月每个月都登录过游戏[平均生命周期=5month]，那么LTV就是
$0.5*5=$2.5
刚才我们说到我们使用流失率来计算用户平均生命周期,实际是很有效的，你大概在一个月后就能知道平均用户会呆在游戏中多久，也包括他们会花多少钱（ARPU），而且我们也能够知道每个用户的生命周期价值是多少（LTV）。通过此，你就可以了解，每个用户对于你的价值是多少，进而你也就明白了广告投放你要为新用户话费多少。
5.K因子[K-Factor]
病毒增长衡量标准。计算如下：
感染率*转化率
所谓转化率指的是当感染后转化为新用户的情况。
如果K-Factor是1，那么就意味着每个玩家都能带来另一个玩家到你的游戏中，游戏不增长，不下降[用户量]；
如果K-Factor是小于1，那么游戏现在进行的营销将会耗尽玩家；
如果K-Factor是大于1，那么你的游戏时按照指数级增长的。
其实，极少的游戏能够做到K-Factor大于1的情况，这也是为什么Zynga在2011年的Q1花费了4000w美元在市场营销上面。所有的游戏需要营销支持发展。当然成功游戏与失败游戏之间的区别就在于成功游戏花钱在营销上，但是却能够从获得玩家身上同样赚取利润。这也是接下来的定义为什么这么重要。
6.CPA
获得每个用户的花费，用于衡量把一个用户导入到游戏中的花费。CPA的衡量多种形式，推荐的形式如下：
新访问者--->注册--->完成新手教程--->变成真正意义的玩家
因此，广告联盟计算是：
总花费/带来的新玩家
比如花费1000美元在Google Adwords，获得1000玩家，那么CPA就是：1000/1000=1美元CPA
未完待续
原文：
1. Churn
The percentage of users who leave your game each month, or sometimes measured as the percentage who leave each week. For example, if a game that has 100 users at the start of the month, and 70 of those users are still playing the game at the end of the month, then we would say the churn rate is 30% because 30 of the original 100 people left that month.
The churn rate can also be thought of as a probability that a player will leave. For example, imagine a game that has 100 players and a 30% of any player leaving (30% churn). That 30% chance of leaving could also be thought of as a 70% chance of staying. So if we want to figure out how many players will be left at the end of the month all we multiply the chance of staying by the number of players at the start of the month. So 70% x 100 = 70 players at the end of the month.
To calculate how many will be left after two months we can simply do it twice, 70% x 70% x 100 = 49 players after two months.
Treating churn as a probability allows us to estimate how long the average person plays your game. The equation is simple: 1 / % Churn = Ave. Player Lifetime. For example, with our 30% monthly churn rate we find that 1 / 30% = 3.3 months average player lifetime.
This comes in important later when we want to calculate how much the average player is worth to us, or the LifeTime Value (LTV).
Ignoring the first week (we’ll talk about that in the Onboarding definition) a social game or virtual world will typically see week to week churn around 5% to 15%. A 5% weekly churn is equivalent to roughly 20% monthly churn. While 15% weekly churn is equivalent to 50% monthly churn.
Phew, that was a long one, don’t worry, the rest are shorter!
2. ARPPU
Average Revenue Per Paying User, usually measured each month. In other words, how much money does the average customer spend (most of your players will never spend any money, ARPPU only includes those who spend money). It can be calculated as total monthly revenue divided by total monthly paying users. Some benchmarks:
- Virtual World: Habbo Hotel: $30 ARPPU (Sulake)
- Online Game: Puzzle Pirates, Three Rings: $50 ARPPU (Gamasutra)
- Social Game: Playdom: $20 ARPPU (Lightspeed Venture Partners)
Club Penguin, on the other hand, has subscriptions and no micropayments. Their ARPPU is somewhere around the $6 mark.
3. ARPU
Average revenue per active user, and like the ARPPU this is also measured each month. The ARPU is calculated by dividing the total revenue for the month by the total number of unique players for the month. Sort of. Depending on the account methodology used it could be said that revenue from the purchase of a virtual clothing item should be amortized over the players lifetime, where as energy and consumables can be recognized immediately. I think that’s just making it all a little too complicated!
From the Zynga IPO filing (link) that the average revenue per user per month is around $0.40. Of course, that’s across their whole portfolio of games. In practice, different types of games monetize better than others.
- Casual Social Game: A casual game is designed for anyone, including those without prior gaming experience. Such as Farmville, Cityville, Bejeweled, Words with Friends. ARPU around $0.10 – $0.20
- Virtual Currency Poker and Casino Games: Traditional gambling games that only allow players to play with virtual currency, such as Zynga Poker, Slotomania. ARPU around $0.25 – $1.25
- Mid-core Social Game: Typically more investment is required to succeed. Tends to be more competitive in nature, and players can be punished for not playing well, such as Mafia Wars and Backyard Monsters. ARPU: $0.25 – $1.25
- Virtual Worlds: Online worlds where players create avatars and interact in realtime, such as Habbo Hotel, Club Penguin, Runescape, and Puzzle Pirates. ARPU around $0.84 – $1.62
4. LTV
The Life Time Value is the average amount of money spent by each player. The LTV includes paying and no-paying players. To calculate the LTV you multiply the ARPU by the average number of months a player stays in your game. For example, if the ARPU is $0.50 and the average player lifetime is 5 months then the LTV is $0.50 x 5 = $2.50.
Earlier we used the Churn Rate to calculate the average player life time. This is really useful. After only 1 month you know roughly how long the average player will stay in the game, and you know how much they spend on average (ARPU) and therefore how much each player is worth over their lifetime (LTV). Through knowing how much each player is worth you can figure out how much you can afford to spend on advertising for new players.
5. K-Factor
The measure of viral growth. It’s calculated by multiplying the Infection Rate by the Conversion rate. The conversion rate is when the ‘Infection’ turns into a new user.
A K-Factor of 1 means every member is bringing one additional member to your game, your game is not growing nor is the game declining. A K-Factor of less than 1 means that without ongoing marketing your game will run out of players. While a K-Factor greater than 1 means that your game is growing exponentially.
It is very rare that any game will ever have a K-Factor greater than 1. That’s why Zynga spent $40,000,000 on marketing in Q1 2011. All games need marketing to continue growing. Of course the difference between a successful game and a failure is that a successful game spends money on marketing but still makes a profit on each player they acquire. That’s why the next definition is so important…
6. CPA
The Cost Per Acquisition is a measure of the cost of bringing that user to your game. The CPA can be measured in different ways. We recommend measuring the CPA as the cost to convert a new visitor from the homepage into someone who has registered, finished the tutorial, and become a player. So the CPA for an advertising campaign can be calculated by dividing the total spend by the number of new players. If we spend $1000 on Google Adwords and get 2000 new players then our CPA is $1000 / 1000 = $1.00 CPA.
