It looks like Twitter could file its public S-1 as early as Thursday afternoon. Sources told CNBC that Twitter sent an email out Tuesday to a group of former employees whose shares are covered by a 180-day lockup period after the company goes public.
Attached to the email was a form from Goldman Sachs for them to fill out confirming that they're indeed part of that shareholder group. They're asked to return the form by 5 p.m. PDT Wednesday, so if the bankers need a day to tally the forms, that means a public S-1 could hit Thursday.
That filing will reveal all the information investors have been dying to see. Of course, we'll see the size of its planned initial public offering, but the most influential statistics will be about the company's growth.
The key metrics to watch are revenue, profits and active user numbers, and the growth rate of those three. These numbers will determine Twitter's ultimate valuation, and how appealing the company is to investors.
(Read more: Twitter to make IPO filing public this week: Quartz)