Remember when EAI vendors talked about the single EAI product that you'd need, the "central" broker that ruled everything? Remember when 3 years later you had three of these products in your system, sometimes from multiple vendors sometimes just different versions that don't play well together, and the toughest job was bridging the gaps between them? Now we have the "Enterprise" Service Bus, and yet again the vendors, including the old EAI vendors, are talking about how you only need "one" ESB which means the proprietary extensions they have and the lack of active process sharing and service definition standardisations don't matter either. This is another great example of an IT salami fraud where they are able to continually "tax" your future projects because they "own" the information. As with the EAI plan however this is just plain wrong and bonkers for companies to sign up for as it will never actually materialise.
Enterprise wide software always assumes that you've chosen the right product for today and tomorrow and that you will never have a merger or acquisition who has chosen something else. The only sensible strategy is to work on a federated model for ESB which means while you have a product that works today you should work on the assumtion that other products will be consuming its services in future. Enterprise wide single product standards in EAI didn't work, and they aren't going to work in ESB either.