Twitter pleased Wall Street with its latest user numbers, but it wants many, many more. How can it get them? One tactic: A new way to greet first-time users who show up at Twitter.com. Twitter has freshened up its sign up page and sign up process for newbies. If this seems like a small thing to you, product manager Christian Oestlien is here to tell you otherwise. It’s a process that took “months,” he said, and is the company’s “first major update in 3 years.”