????現在看來，雅虎（Yahoo）以11億美元天價收購輕博客網站Tumblr已成定局。

????或許我們不應該感到驚訝，因為幾天前雅虎的財務總監肯?古德曼已經表示，雅虎需要再次變“酷”。但是股東們投資雅虎股票是為了拿分紅，不是為了更“酷”。雅虎員工的資產凈值也有一大部分與股票掛鉤。雅虎收購Tumblr的交易可能看起來很吸引眼球，但是它是否會帶來正面收益？

????我相信答案是否定的。

????誠然，僅從數學和公司財務的角度看，雅虎收購Tumblr可以構成一筆很好的投資。雅虎是一個擁有280億美元市值的媒體公司，同時又把重點放在了展示廣告上。Tumblr則擁有大量網頁點擊率，靠做展示廣告賺錢的時機已經成熟了。由此看來，收購Tumblr“錢景可期”。

????根據Quantcast公司的數據，Tumblr每年在美國可以獲得600億次的網頁點擊量。如果我們不考慮增長和國外點擊量的因素，那么Tumblr至少要有將每1000次點擊量轉化為1.79美元的凈收益（RPM）的能力，它的點擊量才能帶來每年1.08億美元的收益。如果再帶入某些數據，1.79美元的RPM預設回報率門檻可能降得更低，這筆收購也就更順理成章了。

????? 廣告網絡可以以1.79美元的價格填補這些廣告位，還有一些搞笑、實用或者漂亮的Tumblr博客可以以10倍的價格直接賣給廣告客戶。

????? 如果算上國外瀏覽量，Tumblr的規模會增大一倍，屆時Tumblr的預設回報率門檻會降到0.89美元。

????? 9.8%的加權平均資本成本有些高了。如果我們轉而使用4.5%的無風險折現率，那么Tumblr的美國RPM預設回報率將下降到0.81美元，包含國際瀏覽量的RPM預設回報率將下降到0.41美元。

????? 雅虎首席運營官亨利克?卡斯特羅是一個聰明老練的展示廣告專家，他知道怎樣把網絡點擊量轉化成現金。[我在谷歌（Google）工作多年，雖然卡斯特羅一向吸引媒體關注的原因是他那不經意的搞笑以及他的薪資政策，但他作為企業高管的水平卻是不可否認的，甚至是受到了低估。]

????? Tumblr很可能會繼續保持增長。在不久的將來，它是值得人們選擇的一個博客平臺，而且它的博主建立的能夠賺錢的博客頁面越多，它的RPM預設回報率門檻就越低。

????It looks like Yahoohas offered to buy Tumblr for the sticker-shock price of $1.1 billion.

????Maybe we shouldn't be surprised, since just a few days ago Yahoo CFO Ken Goldman spoke about the need for the company (YHOO) to be "cool" again. But Yahoo shareholders invest for returns, not for cool. Yahoo employees have a big chunk of their net worth tied to their stock. It may be sexy for Yahoo to buy Tumblr, but will it have a positive return?

????I believe the answer is no.

????To be sure, the power of math and corporate finance can build a good investment case for Yahoo/Tumblr. Yahoo is a $28 billion media business with cash to spend and a substantial focus on display advertising. Tumblr represents a ton of page views ripe for display monetization. It's a bulk play -- Tumblr adds mass.

????According to Quantcast, Tumblr gets about 60 billion U.S. page views per year. If we assume no growth and no international, those pageviews will spin off $108 million per year if a net $1.79 RPM (revenue per thousand pageviews) is achieved. There are data points that can make that $1.79 hurdle rate much lower and strongly favor the acquisition:

????? Ad networks can fill display units at $1.79 and there are some hilarious, useful and beautiful tumblrs for which direct sold brand advertisers will pay 10x the remnant rate.

????? International doubles Tumblr's size. The international page views reduce the RPM hurdle rate to $0.89.

????? The WACC of 9.8% feels high. If we instead use the risk-free rate of 4.5%, then the U.S.-only RPM hurdle rate drops to $0.81, the international-included RPM hurdle rate drops to $0.41.

????? Yahoo COO Henrique de Castro is a smart and experienced display advertising executive who knows how to turn pages into dollars. (disclaimer: I worked in HDC's org at Google for many years and although he draws media attention for his unintentional comedy and pay package - his skills as an executive are undeniable and underestimated.)

????? Tumblr is likely to keep growing. It is the blogging platform of choice for the immediate future and the more monetizable pages its bloggers create, the lower the RPM hurdle rate.