How much would you guess your family tree is worth? If your estimate falls anywhere below the $1.6 billion European firm Permira is about to pay for Ancestry.com (ACOM), dream bigger.

Online genealogy giant Ancestry.com agreed to the sale Monday for a nearly 9.7% premium on Friday's closing share price and 41% more than shares were worth when the company first explored a sale back in June.

Share prices have more than doubled since Ancestry.com first went public in 2009 and attracted other bids from private equity firms Hellman & Friedman and TPG Capital. That's not shabby for a Provo, Utah, company that began by putting Church of Jesus Christ of Latter Day Saints documents on floppy disk in the early 1990s and expanded into a database of 2 million paying subscribers, 10 billion records and nearly 40 million family trees.

Permira's paying a steep price, but Ancestry's pretty substantial for a seemingly one-note company. When the impending sale was announced, Ancestry.com's market cap was $1.3 billion. Its stable of products includes genealogy sites Genealogy.com, MyFamily.com, ProGenealogists, and Rootsweb.com, genealogy software Family Tree Maker and Footnote.com, which holds billions of images of historical records.

It also hosts versions of those sites in Australia, Canada, China and several countries throughout Europe. In the first quarter of this year alone, its sites brought in nearly 1.9 million users. After Ancestry.com brought in Qatalyst Partners as an adviser while considering a sale of the company, it discovered that the site reached roughly 8.5 million unique users in the U.S. alone throughout its existence.

While myriad other non-profit and faith-based genealogical services exist, Ancestry.com is about as mainstream as the family history business gets. It partnered with NBC for its reality show "Who Do You Think You Are?" and spent three seasons helping celebrities like Spike Lee, Gwyneth Paltrow and Rashida Jones trace their family histories before the series was canceled earlier this year.

Even the seemingly benign genealogy business carries some risk for a heavily invested buyer like Permian, though. Late last year, Ancestry.com came under fire for listing the Social Security numbers of recently deceased through the Social Security Master File. While those numbers can be of great help to families trying to map out their family trees, they're also sought-after commodities among identity thieves.

Ancestry has since done away with Social Security numbers of people who have died in the last 10 years and have put the Social Security Death Index behind a pay wall. As its selling price suggests, Ancestry's business is far more serious than fleeting family hobbies or one-off class projects.

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