If you are wondering why twitter is inaccessible from Thursday morning answer is Twitter hit by DOS (denial of service) attack. Official twitter blog confirms the attack. Official words from twitter blog ” On this otherwise happy Thursday morning, Twitter is the target of a denial of service attack. Attacks such as this are malicious efforts orchestrated to disrupt and make unavailable services such as online banks, credit card payment gateways, and in this case, Twitter for intended customers or users. We are defending against this attack now and will continue to update our status blog as we continue to defend and later investigate.”
According to Wired “ In a denial-of-service attack, a malicious party barrages a server with so many requests that it can’t keep up, or causes it to reset. As a result, legitimate users can only access the server very slowly — or not at all, as appears to be the case here. Not only was the site down, but client applications that depend on the Twitter API could also not connect to the service, creating a complete Twitter blackout. According to June ComScore numbers Twitter has more than 44 million registered users and its user base has been growing rapidly for months as it becomes better known in the mainstream.