Facebook Inc.'s decision to relocate to Menlo Park, California, may result in $366 million in new temporary construction spending in the surrounding county, according to study commissioned by the company.

The construction budget is $250 million, and the project may generate $116 million in additional activity, economic research firm Brion & Associates said in a study of the impact over three to four years. It may also mean 2,441 temporary construction jobs, according to the research, released today.

Facebook, the largest social network, is expanding operations while preparing for an initial public offering. The company aims to raise about $10 billion in the IPO, which would value it at more than $100 billion, a person familiar with the matter has said. Facebook also is expanding its satellite locations, including a new engineering center in New York.

The company decided to move its headquarters to San Mateo County from Palo Alto, which is located in Santa Clara County, because it needed more office space for a burgeoning staff. The new headquarters are designed to eventually house as many as 9,400 employees in two adjacent sites. Draft environmental and economic impact reports of the move are being released this week.

The shift may also result in $29 million in total annual retail spending at nearby lodging and retail businesses, Brion & Associates said. The findings were previously covered by the Almanac Online, which reports on community news in Menlo Park.

This doesn't mean the social network is a profitable operation yet. Rather, the cash it generates from advertising and other forms of revenue now exceed the cost of servers and other capital expenditures required to keep Facebook running. One-time costs, like the reported $50 million acquisition of Friendfeed last month, and operational expenses like personnel, are not included in this equation. Outside investments in the company, like the $200 million it raised from Digital Sky Technologies in May, are not accounted for either.

Facebook has never disclosed its revenues, but board member Marc Andreessen recently told Rueters that the site is on track to generate over $500 million in revenues this year.

The same day it announced its cash flow milestone, Facebook said it has added 50 million users in the past two months -- bringing its total user base to 300 million and its signup rate to roughly 806,000 users per day.

That's a huge amount of traffic to support, and the site's accumulating stockpile of photos, videos, and other content requires an ever greater number of expensive servers. This was a serious problem for Facebook as recently as March, when my colleague Spencer Ante reported that it was seeking $100 million in debt financing directly related to server costs. Now, it appears that economies of scale are working in the company's favor: the more members it attracts, the less it has to pay to support each one.

This is a positive note for new CFO David Ebersman, who came from Genentech in June, to start his career at Facebook. But his work has just begun. The next two priorities at Facebook are likely to be creating new sources of revenue -- such as virtual goods and customized ad campaigns -- and taking the company public.

Facebook's announcement is also a positive sign for the broader social networking space, long derided by critics as a business high on hype and short on real profits. With the poster child of social sites well on a path to profitability, venture capitalists and strategic buyers will be more likely to bet big on Facebook's smaller rivals.

Here's the chart:

Much has been made of the aging of Facebook, but the sustained rate at which baby boomers and seniors are joining the site is surprising. It seems that we're past the point where you could call this a fad -- older folks are continuing to join the site because they're seeing their friends and family members living their lives on the site and don't want to be left out.

What does this mean for Facebook? It's a valuable opportunity for advertisers on the site, who would like to reach older Americans with more buying power. But the company will have to also think about how the site should evolve to accommodate the increasing diversity of its members. For example, baby boomers appear more interested in intimate communication with their family, and some of them feel like they can't get that on Facebook.

iStrategyLabs gets its numbers from Facebook's Social Ads system, so they're reliable. But it's important to note that this information is not obtained through surveys -- it's pulled from user profiles. That means that whatever personal details users leave out of their profiles -- such as school affiliations, home towns, and even ages -- won't show up here.

On Monday, iStrategyLabs posted numbers Facebook supplies to advertisers which show a decline in members identified as high school and college students from January to July. The 16.5% drop in high schoolers and 21.7% drop in college students appear particularly surprising, because they coincide with a 513.7% rise in users age 55 and older.

But before everyone goes searching for the new cool site where all these young people are flocking, I suggest looking at what these numbers really represent. They are not survey-based -- no one asked Facebook users whether they're in school. Rather, the data is based on which Facebook users choose to identify the school they attend on their profile pages.

And what happened between January and July? Millions of young people graduated from school, giving them reason to drop online affiliations with their alma maters accordingly.

Graduation alone might not explain the drop. Perhaps because of increased concern over privacy issues in the past year, many users may simply be choosing not to identify themselves with specific schools. These "networks" which were so instrumental to the site in its early days (when you had to belong to a particular to school to even join) are losing relevance as more of the general public enters Facebook and people cross-pollinate with many different groups. The company itself decided to place less emphasis on networks in June, when it announced it would be eliminating geographic networks from the site altogether.

The changes, which will be tested with 40,000 members in the U.S. in the next week and around the world the week after that, don't add a lot of new options so much as make them simpler to access and set. Facebook hopes the new system, which consolidates 40 different settings on six separate pages, will encourage people to become more comfortable with posting items as freely as they do on Twitter and other services.

The gist is this: You will be able to go to one page to set whom you want to see whatever you post or personal information in your Facebook profile: from just friends to people in a chosen network you're in to the whole world--which means people who aren't Facebook members too, unless you're a minor. And if you want, you can change those settings for each piece of content you post--such as a job complaint you want only close friends to see, not your company network. A "recommended" setting will make your basic info and content posts public--in other words more Twitterlike--but provide more privacy for other things like Wall posting from others and contact info.

You can get the details on the privacy enhancements at a slide show here (and embedded above), as well as on the Facebook blog, which you can also read after the jump here.

The upshot: While the new system is clearly simpler, and will be presented by default when people initially try to post content, I suspect it will still be too much for some people to bother with. The basic problem is that Facebook aims to offer many kinds of messaging, from intimate posts to friends to rants you want the world to read. That inherently involves people making choices, sometimes post-by-post, inevitably making the process more complex. (One blogger, Jason Kincaid at TechCrunch, thinks the new system is a looming disaster because too many people won't realize the implications of public sharing. I'm not so sure it will be worse than it is today, though.)

Twitter is popular partly because it's so simple: Posts are public, or they're not. It's to Facebook's credit that it's providing choices, and to its further credit that it's now trying to make those choices simpler. But it's no sure thing yet that the new system will keep Twitter from becoming the Internet's biggest community bulletin board.