Sean Parker has had a hand in some of the Valley's biggest successes. His first company, Napster, took the world by storm, but didn't make Parker rich. His second, Plaxo, just sold to Comcast. And his third, Facebook — well, say no more. Except for the bit about him getting kicked out, according to Mark Zuckerberg's legal testimony, for a cocaine arrest. (Parker characterized the incident as "a misunderstanding.") That and more is covered in the 21 pages Sarah Lacy devotes to Parker in Once You're Lucky, Twice You're Good, new book about Web 2.0. The index page where Parker is listed:

Everyone has a little online jackass in them; some of us add people on Facebook too soon, some of us beg for votes on Digg, some make white whines on Twitter. But these behaviors can lead to more annoying habits, like constantly bugging people to blog you, getting hooked on Yelp, or writing drug metaphors. Thank god online jackassery can be summed up in a condescending online quiz. Take it below! Maybe you're a Carrie.

The president of the United States, George W. Bush, has been banned from sending emails during his term in office, with officials citing security concerns. That's all about to change once he's termed out of office — soon friends and supporters can expect a steady stream of "You know you're a redneck when" forwards, links to GodTube videos, and the like. It's only a matter of time before he sets up a Facebook profile and starts Twittering, which I'm pretty sure was predicted in Revelations to be one of the signs of the impending rapture. (Photo by AP/Ronen Zvulun)

This morning we posted the "Nefarious O Value" theory of the mystery Facebook Stalker feature. Now, a second tech-savvy tipster writes in with step-by-step instructions for how to find Facebook's unexplained "O" ranking for every single one of your friends on the site. In other words—from what we can gather, at least—there's a file on your computer that tells you exactly how the site's algorithms rank each and every person in your social circle. The instructions are after the jump. Please write in and let us know what your results are. The code may soon be cracked!

Due to a souring economy and a shift in spending from Facebook itself to third-party developers who place widgets on the social network's site, market research firm eMarketer lowered its projections for Facebook's 2008 ad revenue from $305 million to $265 million. eMarketer expects ad spending on widgets and applications — which goes to their makers, not Facebook — to reach $40 million this year.

Facebook is building a Jabber/XMPP interface for Facebook Chat, which means users can access their Facebook friends list from other instant messaging clients such as Trillian, Apple's iChat or Pandion, not just the Facebook website. [Facebook Developers' Feed]

In late May, Facebook will launch a Contest/Sweepstakes application to allow marketers to cajole Facebook users into becoming "fans" of their clients. Australia's Carl Williams needed no such fakery to build his Facebook fanbase — just a 35-year prison sentence for three murders and drug trafficking. Williams can claim 974 Facebook friends, according to the Sydney Morning Herald. A Facebook group which implores members to "please sign this petition to secure the release of our favourite Melbourne gangster Carl Williams" has 423 members, with 74 having joined this morning.

Union Square Ventures funded Mark Pincus's casual games maker Zynga with $10 million not long after Max Levchin-founded widgetmaker Slide raised $50 million. Competitor RockYou wants a round of funding that would value it at $400 million. We like to scoff at these purveyors of online sheep-throwing tools, but that's serious scratch, people. In this excerpt from a longer interview with Kara Swisher, Zynga's Mark Pincus explains what widgetmakers see in our future — and shows us exactly what kind of pitch VCs are going for these days.

A clever tipster sent us this Facebook screengrab, which details Marc Jacobs' ever-changing boy business. Hopefully the highly successful fashion designer changed his "Status" from "In an Open Relationship" to "It's Complicated" because his new upscale boyfriend asks for a slower, more old-timey courtship process. (Versus what, we presume, was happening before: "Hi, I'm Marc" leading to an immediate dropping of trou.) It is terribly complicated indeed. Also of note: Liz Coen has an adorable dog. And can I get a holla from the back from all y'all who don't know/care about Facebook jargon!

Yesterday we posted five theories about the mysterious Facebook Stalker feature—the one some people think is an undercover way to identify those ex-lovers who are still pining for you, although that is totally unconfirmed and probably false. But we have to admit, none of those theories involved any weird computer language or technical terms. But an astute reader has sent us a theory that, based on the fact that I can't really understand its technical talk, sounds very insightful. We'll call it the "Nefarious O Value" theory. The full email is after the jump.

When OKCupid, the site where Internet users too cool to date online date online, needed some fresh blood, founders Sam Yagan and Chris Coyne took a page from the sex business to stay afloat: dates on demand. Describing the premise of CrazyBlindDate.com, which matches users by location and a vague sense of mutual compatibility that has more to do with scheduling than anything, Yagan says:

Aha—Facebook has issued a statement on the mysterious stalker feature that we spent all day covering: "Facebook tries to surface the people we think are most important to users to make it easier and faster for them to navigate the site and find what they are looking for...The search drop down is not a list of those that have searched for the user. It is also not a list of people whose profile the user has viewed the most or who have viewed the user's profile the most. To avoid any confusion, this will no longer appear." See, you were too stupid to handle it! But wait: as our commenters figured out in about one minute flat, typing a period (".") in the search box brings up the same five-person list. And are they really your "most important users?" Random. We urge continued experimentation.

And it's gone! It appears that the mysterious Facebook stalker feature—that allowed you to call up the names of five people who (we think) were searching for you most, just by pressing the down arrow in the search field—has been disabled. Our post on the feature went up shortly after 1:00; by 4:30 (or possibly earlier, based on our comments), it was no longer working. They're quick! We have an email in to Facebook to find out exactly what happened. How could they take it down without even explaining what it was? They mystery is eating us up inside. We will find the truth. [UPDATE: As noted in the comments, it looks like simply typing a period (".") in the search box will still bring up the same list of five people. Hope is not lost!]

We've updated our earlier post about the mysterious Facebook search feature that brings up the names of people who may or may not be searching for you. Five of the most intriguing theories about the feature are now appended. But the mystery remains officially unsolved... for now. [Who's Stalking You On Facebook?]

Maybe you don't know who Engage.com's Julian Brass is? Odd. Because the 43 people tagged in the farewell-to-San Francisco video Brass uploaded to Facebook do. One of them forwarded it to us with this note: "This is the most painful shit I've ever seen in my life from Engage.com's Julian Brass." Really, how would we not share it with you after such a cold tribute from a so-called friend? Our favorite part is when Brass points the camera at his Francisco Street home, where he lived for all of a year and a half, and says, "I always just said: It's the pink one guys; it's the pink one. Ha ha." After viewing our excerpt, go check out Brass's full seven-minute video, slideshows and all. We're out of words to describe it, having previously banned them all.

A tipster notes that if you go to your Facebook page, click on the search box, and then hit the down arrow, up pops a list of the five people who search for your name most often. It seems to work! Although maybe it's just five random people. And maybe you all know this already? In any case, it's something to talk about with nerds. UPDATE: Well, this post has generated quite a bit of disagreement! Below, five thoughtful theories attempting to solve this pressing mystery:

When Google took on Facebook in ultimate frisbee, Facebook took the series 2-0. Now we hear a contest of beer pong — the drinking game involving ping pong balls, Solo cups and Milwaukee's Best — has been scheduled between Mark Zuckerberg's finest and the New York-based, IAC-backed CollegeHumor. CollegeHumor cofounder Ricky Van Veen began the smack talk early posting the above image to his blog. It reads:

The person who created a fake Facebook profile for Dean Tim Puntarelli of Roncalli High School in Indianapolis likely felt comfortably shrouded in Facebook's seeming anonymity as he sent "inappropriate" pictures from the account to students. No longer. A local judge ordered Facebook to reveal the prankster's IP address to Puntarelli; the Archdiocese of Indianapolis which runs the school calls it "identity theft." (Photo of a priest with a cane by Paweł Kabański)

Peter Thiel, the famed venture capitalist who cofounded PayPal and funded Facebook, has not spoken about his private life since Valleywag broke the curious silence about the gay entrepreneur's sexuality in December. (He hadn't really discussed it before then, either.) But it has again become the topic of conversation. Out has put him in tenth place on its Power 50 list of prominent gays and lesbians. The magazine praises him for his multibillion-dollar hedge fund (Out says it's worth $3 billion, but we've heard $5 billion) as well as his $1 billion stake in Facebook and his funding of the Methuselah Foundation, an anti-aging research group. Knowing Peter, we suspect that none of this bothers him particularly — except for the fact that he wasn't No. 1.

Despite her protestations of innocence, it's pretty obvious that Facebook COO Sheryl Sandberg had a hand in getting top Google flack Elliot Schrage to follow her to her new employer. She's not alone. One Facebook insider recently observed that for every Googler hired at Facebook, they pull another four former colleagues with them. The place is getting "overrun," says one close observer of the company.