Following last month’s leak of confidential information, we discussed Twitter’s plan for subscriber numbers . Although few of us had heard of Twitter 18 months ago, Twitter hopes to have 100m signed up by the end of 2010.

Well if their latest unique user figures are anything to go by, it seems that they are well on the way to reaching that target. According to ComScore, Twitter’s traffic soared to 51.6m users in July. That’s up a whopping 16% on June’s 7.1m users. And what’s interesting is that almost all these new visitors are coming from outside the US.

The US user base grew from 20m users in June to just 21.2m in July. US users represent 41% of the total site traffic. International users by contrast, which represent the remaining 59% of users, went up by a massive 55% in July. We revealed just a few days ago that London is Twitter’s top city.

There’s no doubt that Twitter’s role in international crises have helped promote it to a more global audience.

These figures could in fact mask a much higher user base. ComScore only count traffic to the website Twitter.com, and not all the traffic from people using Twitter applications, such as TweetDeck and Tweetie. Many millions choose to use the service using apps rather than the website itself.

To further underline the fact that Twitter is not for Teenagers, ComScore also said that just 11% of Twitter users are between 12 and 17.

It seems that our enthusiasm for Twitter know no bounds! And this is helped no doubt by all the free press coverage that the micro blogging service is good at generating.

Is it time you signed up to Twitter too? Or are you sick of reading about it on here?! Leave us a comment below.