When launching a new service, entrepreneurs have a myriad of things that make them nervous. Maybe the product won't be seen as having value. Maybe competitive offerings are good enough. Maybe there are bugs that nobody has discovered yet. And sometimes, the rush of new users who arrive to kick the tires is enough to break the system, as the infrastructure is not ready. To help reduce such public outages, many products start out with a small audience, and there are many ways to grow slowly, each with their own pitfalls.
1. The Closed Private Beta
Often sites will have a private beta period, open only to a known set of users, typically starting with the company's inner-most friends and supporters. In order to get onto the list, you have to know somebody at the company, or be so influential to gain early access.
The upside for a private beta to the developers means that typically the product is in safe hands of people who understand what you are doing, and are willing to forgive rough edges and mistakes. Also, the small load means you can fix bugs leisurely without the threat of public exposure.
The downside for the private beta is that the site itself still isn't really being tested by a more natural audience, either in terms of how they plan to use the service, or in terms of scale. What might work during a closed private beta might not be good enough when the doors open.
2. The Private Beta With Open Invitations
Sometimes, a site will start with a private beta period, but users can invite their friends - often a limited number. You saw this with GMail back in 2004, when early users could invite others, but only a few at a time. Similarly, FriendFeed did the same in 2007, as did Toluu in 2008, closing their early sites off to the mainstream, but letting you in if you knew somebody who had already gotten through.
The upside for this process is much like the closed beta in that the audience is going to be relatively forgiving and small. Also, the influx of less-known people can give a more realistic expectation of what features are needed and which need to be improved.
The downside for this process is that there may be people who could help try the product who don't have an in, so their interest is muted. Also, the small group tends to be insular and will use the product differently than an open audience.
3. The Numerically Limited Invitation Beta
After internal testing, some products will release a known quantity of invites, either through their Web site, or the media, in an effort to expand the testing, and give early users a flavor of the site. The invites, often tied to specific sources for tracking purposes, can range from few dozen to hundreds or even thousands, depending on how robust a test, and how deep the infrastructure. We've recently seen this approach with the site Lazyfeed, which gave out a few hundred invites in the last week by way of TechCrunch, ReadWriteWeb and from me, both on FriendFeed and Twitter.
The upside in this case is that this wave of users best simulates actual usage of a product, to see what is working and what is not working, while stressing the system's back-end only to a predetermined level.
The downside is that users who don't get to the invites quickly can get discouraged, and often, the very first people to get in aren't necessarily the ones who will most deeply investigate your product, but instead, happen to be those who were fastest at getting to the news and signing up.
4. The Open Beta
For some services who don't want to limit the testing, they might open up a site to all who wish to register, but do so under the guise of a "beta" tag, explaining that some features might be missing and others might break. While anybody can enter, they should not assume full functionality. You could see this with GMail for years, even after the product went away from strict invites.
For developers, the upside here is that they have a perpetual excuse for problems. But it's beta! Also, any user who wants in can get in, without having to get on a list or know someone. It also can often give the ability to stress-test a product under the impact of a large audience.
Downside is more limited, but can be seen if users are more wary of beta products, preferring to wait until they are more stable for use.
5. No Beta
Some products might skip the beta process altogether. They are just open for business, period. This removes the guise of the testing period and lets the entire audience at them at once. I call this the "Open. Fail. Scale." method, because often there are bumps along the way that come with growing a product, and one can never anticipate them all. Twitter would be a fantastic example of this, although both its fail and scale have gone on more than anticipated.
So how do you choose, if you are an entrepreneur, how to get your product out the door? You can see, for instance, that Brizzly, by Thing Labs, is still in Private Beta. (And I want in) Lazy Feed is opening up more, and you can get an invite here. They each may have their own reasons. In the example of Brizzly, it's probably not ready yet. For Lazyfeed, maybe they aren't ready for a million support questions and they want to start slow.
I tend to believe you should open as big as you possibly can without breaking. If users want to get in to your service, don't stop them in their tracks. Just set expectations and work with them as partners to continue to improve. Don't insult them by using beta as an excuse, but instead as a stepping stone. And yes, get me in as early as possible. I promise I won't break anything.