Twitter celebrated its sixth birthday on Wednesday by dropping an impressive stat: The network now claims 140 million active users.

In a blog post feting the event, the company also boasted that its network sees 340 million tweets a day. "That's more than 1 billion every three days," the post reads. "However concisely, it turns out there's plenty to say."

The post also includes a photo of co-founder Jack Dorsey's sketch of the service he envisioned (see picture)

The 140 million figure is a 40% increase over the 100 million active users Twitter CEO Dick Costolo claimed in September. At the time, Costolo said those 100 million users log in at least once a month and 50 million go on every day. Twitter's post didn't disclose how many of the 140 million are daily active users.

Costolo also said at the time that 55 million users log on to Twitter from their phone or tablet every month. Twitter.com was also seeing 400 million visitors a month, up from 250 million at the beginning of 2011, Costolo said in September.

With 140 million active users, Twitter is just behind LinkedIn, which claimed 150 million members in February, and ahead of Google+'s 90 million (although at least one analyst says Google's social network has 100 million users).

Facebook, meanwhile, revealed in February that it now has 845 million users on its network.