I don’t know for sure of course, but I believe that they are ordering batches (called a production run) of filters to be manufactured for them, and as soon as they arrive, the people who signed up first on the list get the filters from the batch that comes in.
I’m guessing it takes about three to six weeks for a batch to come in…but there is no way to know how many they are ordering in each batch, or how many the company is capable of manufacturing at one time, so there is absolutely no way for them to tell individuals when they will get one until their names come up next on the list and they have a batch in hand.
This isn’t a situation where the filters are available in a store for people to walk up and purchase, they are being manufactured to Glowforge specs. It’s like buying a custom car or boat…it takes time to make them.
As a customer…the one thing you can do if you want one, is to get your name on the list early. The longer you wait, the more people wind up ahead of you. The ones who have them now signed up for them on the first day, and they had a small batch available. The next batch to get them will the ones who signed up in early days after the announcement.
And it’s still pretty likely that the Compact Filters will be in your hands before the Glowforge filters, even if you sign up now. So factor that into your decision making.