Since its launch in 2006 micro-blogging service Twitter has become a social media darling, raising a total of $160 million since its 2007 Series A.Since its launch in 2006 micro-blogging service Twitter has become a social media darling, raising a total of $160 million since its 2007 Series A. (CBC)How do Web startups raise money? The answer accounts for a huge corpus of tech and financial discussion, but it can be condensed into an eight-word statement: Someone somewhere thought he'd make his money back.

If you consider a few notable fundraising efforts from popular Web startups, you begin to see how this hypothetical "someone" might think his investment would be prudent and even profitable. Here are five popular Web startups we've seen raising large amounts of money since the 2008 downturn, and a quick look at how they were able to do so.

Groupon

Groupon offers daily discounts for local businesses; these coupons can be redeemed only when a significant number of people choose to use them. For example, Groupon recently partnered with Gap to offer shoppers $50 US worth of clothing and accessories for $25.


While daily deals and critical-mass coupons are fine and dandy for retailers and consumers, Groupon also takes its cut. The company usually keeps half of the coupon price and is expected to report $400 million in revenue for 2010.

Groupon has brought in increasing interest from investors. Since its relatively modest $1 million angel round in 2007, this startup has gone on to garner a total of $173 million over the past three years, the vast majority of which was raised after the 2008 economic crash. After collecting $6.8 million during its Series A round of funding, Groupon managed to bring in $30 million during its Series B round in December 2009, which was led by Accel Partners. Its headline-making $135 million Series C was led by Digital Sky Technologies, the famous investors behind Zynga and Facebook.

Without question, having a revenue stream as a core part of the company's main product is a popular feature (with VCs) of funded startups. Groupon has that covered. Aside from the value the product offers, at scale, it also is intended to generate massive amounts of revenue. Unlike some social-networking apps that require partnerships and advertising dollars to support an unrelated product for end users, generating revenue is Groupon's most basic function.

Zynga

The creator of popular casual games, including "FarmVille" and "Mafia Wars," boasts a revenue model based on small end-user transactions in virtual currency, which users spend on virtual goods. Zynga has proved that microtransactions at the scale of Facebook's platform are big business worth serious investment.

Despite violating a core tenet of Web startup wisdom — never build your business on someone else's platform — Zynga has racked up huge rounds and equally huge valuations. All told, Zynga has taken $519 million in funding, the bulk of which was raised after December 2009. In that month, the company closed a $180 million Series C from such firms as Andreessen Horowitz, Digital Sky and others. And in June 2010 Zynga took a $300 million Series D from Google and SoftBank. With more than 56 million Americans playing social games, it's no wonder why investors are putting down serious money in this industry.

Twitter

Since its launch in 2006 micro-blogging service Twitter has become a social media darling, raising a total of $160 million since its 2007 Series A. The company raised $135 million over two rounds in 2009 from such firms as Benchmark, Morgan Stanley, Union Square and others.

Notably, all this money was raised before Twitter had found any significant source of revenue. This fact bucks a major trend in investment (that VCs like to see clear revenue stream before investing), but Twitter pulled it off because of one major factor: People.

Not only was the service growing exponentially, but it also had the endorsement (and daily usage) of pop culture celebrities such as Ashton Kutcher and Justin Timberlake. But nothing topped Twitter's Oprah appearance, a watershed moment that brought a deluge of mainstream attention and a glut of new users.

Between the escalating adoption and increasing media attention, Twitter has become an opportunity investors can't turn down.

Asana

Facebook cofounder Dustin Moscovitz and Facebook engineering lead Justin Rosenstein teamed up after leaving Facebook to found Asana, a startup that is reportedly building project management software. It is still in early development and hasn't launched a product yet. This is one case where the product is presumed to be a sure bet because of the past experience and intellectual caliber of its creators.

Sometimes, a startup can raise money with nothing but pure pedigree. When a handful of big tech company engineers leave the mothership to found a startup, as happens in Silicon Valley from time to time, they can often drum up a round of funding before pencil meets paper.

Over seven months in 2009, the team was able to raise $10.2 million in two rounds of funding. In this case, investors are banking on Moscovitz's and Rosenstein's past successes. In a way, it's as if they are investing in Beethoven's next symphony or Van Gogh's next canvas (i.e. the next Facebook).

Ustream

Finally, there's Ustream, a live interactive broadcast platform, which raised an impressive $75 million round of funding earlier this year from SoftBank. Previously, the startup had brought in nearly $13 million between a small 2007 seed round and a 2008 Series A. That's a huge jump.

Despite a range of competitors in the online video world, including YouTube, Ustream has made its mark on the live video market. Ustream has demonstrated mass-scale success in this arena by brokering deals to show live online footage of red carpet events, celebrity press conferences and even the 2008 Presidential Inauguration.

While challenging an industry leader like YouTube isn't usually a prudent path to funding, doing so successfully through innovative technologies and user acquisition strategies can pay off.