http://www.bbc.com/news/world-middle-east-40155829
I think this is actually pretty interesting news, even though it might just be posturing - certainly the current moves regarding Qatari visitors to several of the countries in question as well as airlines shifting routes away from Qatar suggest that they might be serious. Qatar has always been a little unusual in the Gulf; they have a pretty active foreign policy on a number of fronts: running al Jazeera, financially supporting a variety of Muslim Brotherhood-related organizations (including the old Egyptian government and Hamas), and having a pretty interventionist military stance (e.g. Yemen and Libya). That's not so crazy - after all, UAE/Saudi/Egypt also have their own brand of interventional policy (Bahrain less so). But Qatar has shown it is willing to go alone, often bucking against the wishes of the biggest Gulf patron (the US) and wading into pretty complex situations without much coordination (e.g. Libya).
The Saudis and Egyptians, on the other hand, tend to stay local in their interventions and then coordinate with the US to some extent (e.g. Yemen). The UAE is even more distinct; they have cultivated a very high end military capability and have developed a close relationship with the US through substantial deployments in Afghanistan and a very active role in the bombing campaign in Iraq/Syria against ISIS (interestingly, I read an article a while back saying that UAE fighters were the only non-US coalition country that was tasked with attacking the best defended and highest risk targets; typically these are only carried out by the US due to a combination of technology and training, but the UAE made the cut); what they don't do is go it alone. Bahrain has outsourced their naval security to the US and their regime stability/internal security to Saudi Arabia and do not rock the boat otherwise.
I guess that the Saudis et al decided that Qatar needed to be taught a lesson, both on their somewhat cowboyish stance on foreign affairs as well as their support for Muslim Brotherhood and other Sunni religious organizations, which Egypt and Saudi in particular see as threats to their stability. The timing seems a bit odd to me, though - reports have tried to link it to a hack (or something fishy) of some Qatari media that posted (apparently?) false stories quoting the Qatari leadership as being more kindly disposed to both Iran and Israel (likely the former is what would ruffle feathers), but I am less than convinced that this is the real reason. Has anyone been following Gulf politics closely enough to understand what's really going on?