Do you create an individual invite code for everyone who signs up to try your beta? Or have some codes which can be used multiple times (eg works for 10 signups)?
Are there any sites that manage the whole process of people applying for invites, sending out invites, etc? Inviteshare.com is the nearest thing I could find, but it's geared more towards exchanging invites between users.
A) Create one invite code, send that to a lot of people. B) From the people who sign up, give each new account an invite code itself, so that person can sign up. You can assign a random string or set a class for 2nd degree invites. C) Repeat step B, and adjust invites accordingly to the amount of growth.
A prerequisite for Step B is making sure that you have invitations built into the system, so that people it won't be ignored.
Some good features to have for a ticketing system: - ability to type in an email or set of emails and it automatically sends a different beta code to each address - ability to have one invite be able to create more than one account (sometimes we send a code to a company and tell them to create a few accounts for their staff, each invite can create X users before it expires) - have a date expiry on invites so you can toss-out old ones
To me Beta is pretty much something that's ready to go prime time, everything works, you spent a few days testing it to make sure you don't crash the system, but you still want to spend some time with a much larger audience testing it to sort out all the missed bugs. Alpha to me is when you just finished coding it up and only did the most basic stuff to check if everything works.
If its an alpha then use the one at a time invite, if its beta set max # of users and use one at a time method if you need to give out some extra invites to more valuable testers
A larger problem (you're not alone in making this mistake) is trying to lump software development into set, solid stages. Development is more fluid then "OK. we're beta. next up is final release and we're done forever." It's doubtful that you ever stop adding features or making something better. And if that is the case, I'm not entirely sure I'd want to use your product knowing it'll never be improved beyond 1.0.
As for why you might want to limit invites? Maybe you're trying to figure out how much it can scale with what you currently have before you work on it some more? Or maybe you want to try the limited scarcity thing out. Who knows the motivations.
I'm a luddite: I ask people to send me an email if they want to beta test, and then when I'm ready for more beta testers I go through my inbox, create accounts, and send out emails.
You might find something if you google for "coupon manager" or something like that.