The problem is that, everyone else feels excluded and the quirks, habits and best practices of Twitter, not to mention some core features, are not so easy to pick up and are not too apparent from the get go.
As Twitter struggles to move past its user base ceiling, it needs to make the site more intuitive for new users and the company is taking steps towards this.
One example is a new feature now in testing, a small one, but one that illustrates exactly what Twitter is struggling with and what's it's trying to change.
Twitter is testing a new profile page that enables users to send public tweets directed at those users, @replies in Twitter terms, directly from the profile page.
Regularly, users have to add @twitteruser to their messages if they want to reply to someone else's tweet or talk with another Twitter user publicly.
The popularity of Twitter have made the @reply syntax and usage quite widespread, but that doesn't mean that new, non-technical users will catch on from the get go what it's all about.
And a curious new user who doesn't know how to engage with the service or is not encouraged to do so is a user that is not going to visit the site too often and who may not be eager to give it another shot in the future.
Of course, Twitter is going to have to do a lot more than this to make the site more appealing and easier to understand for new users, but at least the company has recognized the problem. And the new funding it's rumored of raising should come in handy as well.