Heads up, y’all—Twitter’s going public.

The company announced today, appropriately via a tweet, that it’s filed with the Security and Exchanges Committee for an initial public offering. Goldman Sachs is said to be underwriting the effort, and its public value is expected to be between $15 and $20 billion.

The news isn’t exactly a shocker; it’s perhaps more surprising that it took the company so long to go public.

Veteran tweeters have surely noticed the introduction and gradual increase of advertisements on the site since its 2006 debut. In 2010, it started offering promoted tweets, and last February, it introduced an advertising API, which makes marketing on Twitter more efficient for advertisers and easier to integrate Twitter ads with existing promotions. A month after that, it rolled out another service that let advertisers target Twitter users based on keywords in the users’ tweets.

This was all in anticipation of the IPO; the company makes its money via ads, and it’s thus essential that it demonstrate the viability of its advertising services in order to attract investors. It’s impossible to say precisely how this will effect the Twitter experience for every day users, but it’s likely that ads will become both more prevalent and more seamlessly-integrated into the service.

$20 billion is a whole lot of money, no doubt, but it's a small fraction of Facebook's $100 billion IPO.