The velvet rope: 10 exclusive tech betas

The private beta is an art form. It can make a service seem exclusive and important, even if the site's creators are just trying to keep it from imploding from an influx of new users. While Web developers have long used this control system to do pre-launch bug mashing, certain sites have made it something memorable--even if the product ends up being a dud.

Gmail, circa 2004, is one of the best examples of a private beta done right. Google intentionally limited the number of people who could use the service, but built in an invite system that would let users give access to friends and family. What ensued were a number of trading sites where users could exchange favors or services in return for an invite. Google eventually opened the service up to everyone, but for a while the hottest ticket in town was a Gmail invite.

Here are some of our favorites from the past few years:

Google Wave
Status: Still closed
This is the Web beta everyone wants in to today. It's a cool new communications platform that melds e-mail, instant messaging, and collaborative editing. But here's the thing: as interesting as it is to experiment with (we're in it, nyah nyah), it's mostly useless since you can't really talk with anyone in the real world on Wave. Only selected developers and press are in it now, and users don't get invitations to give out to friends. And who wants to talk to us?

Google Voice
Status: Still closed
Here's a closed Google beta that is useful, though: Google Voice. This incredible service gives you a new phone number with nearly every useful telephone feature known to mankind: it screens your calls, it forwards calls to other phones, it dials out (indirectly, but still). It receives and sends text messages. Currently, only people who got on to the previous version of the product, Grand Central (which Google acquired) have access. That's a bummer for everyone else. It's fantastic. When it opens up (Google won't say when), get it.

Wolfram Alpha
Status: Opened May 15, 2009
The not-a-Google-killer "knowledge engine" was hyped to absurd levels for months before it was shown. Then Wolfram founder Stephen Wolfram held a series of over-the-Web product demos to froth up the geeks even more. Finally, a few lucky souls got access. It opened up to the public a week later. In this case, we understand why the developers held off on opening it up. Wolfram Alpha is an extremely interesting service but it's picky about syntax. For most users, it still makes for a better gee-whiz demo than it does a day-to-day productivity tool.

Microsoft Bing
Status: Opened June 1, 2009
If you can't buy 'em, build 'em. After the Yahoo negotiations fell apart, rumors started to circulate about a new Microsoft search initiative, code-named "Kumo." Could Microsoft finally get search right? Access to the private beta was doled out to a few journalists in late May, giving the company only a few days to do damage control before the scheduled public rollout in early June. Fortunately for Microsoft, the reception for Bing was welcoming, even if most writers started off skeptical.

Boxee
Status: Open as of January 8, 2009
Boxee is home theater software that taps into music and video from all over the Web, along with whatever is on users' computers. It's currently available only on Mac and Linux machines, although it's headed to Windows later this year. The service made its debut in mid-2008, although was in a tight private beta for the remainder of the year. After CES 2009 the company began to let more people in, however the private beta may come back when the Windows version comes out of alpha.

Trillian Astra
Status: Open as of June 9, 2009
Before sites like Meebo came around, one of the only ways to chat on multiple IM networks at once was Trillian. The popular software client let you sign on to AIM, Yahoo, ICQ and more--all at once, and in one app. Astra is the latest version of Trillian, and has been in private testing for close to three years. We scored an early look at it in 2007, and it just took off its private beta status on Tuesday. When it launches, it will have both free and premium feature; this makes it a little long in the tooth compared to most of today's chat software, which comes open-sourced and free of charge. (You can download Trillian Astra here)

Hulu
Status: Open as of March 12, 2008
Hulu was one of the most groundbreaking products of 2007. It did what content providers should have done years ago, and put full TV shows online with ads. Its 18-week private beta wasn't all that long in the history of betas, but in the first few weeks it was near impossible to get access to the site if you didn't know someone with a spare invite.

Joost
Status: Open as of October 1, 2007
Web video streaming service Joost was in private beta from early February of 2007, all the way to October. What made it especially noteworthy early on is that it used a token system to dole out invites you could give to others. That, and it had huge buzz since it was being created by the same folks who created Kazaa and Skype. The site has since split from its desktop software roots and reimagined itself as a YouTube-like site for professionally-created content.

Spock
Status: Opened in August 2007, but recently shoved behind a paywall
The people search engine Spock was rolled out in demo, then into a controlled beta, and finally to the public in 2007. As always, the tech world was eagerly awaiting this new search engine, so they could compare it to Google. Not really: people wanted to see what Spock said about them. Nothing like narcissistic curiosity to drive people into a new product. Sadly, Spock has since adopted a very tight pay wall that puts most of its data behind a $20 subscription fee. You can probably get most of the same data for free on the open Web.

Wattvision
Status: They're still building gizmos
This YCombinator green tech start-up is taking a unique approach to energy monitoring: to use it, you literally stick a gizmo on to your electricity meter that watches the little wheel turn around. The data is transmitted to back to the Wattvision servers, where it's then packaged so you can see it on the Web or an iPhone app. Everyone who's seen the presentation wants this product. While energy use tracking will eventually be built into appliances, until that happens you need something like this to get data more granular than your monthly bill gives you.

Did you have a private beta you're particularly fond of? Or did we leave one off? Let us know in the comments.