It is fantastic to see IE8 up the ante on concurrent connections from 2 to 6. I would love to know how they made the call for 6. It sounds reasonable. You don’t want too many else you could end up sucking down so much content at once it could freak out the browser (e.g. imagine a bunch of video on a high speed line).

This should mean, for some situations, that you may not need to deal with www1, www2 type hacks to split up your domains. Of course, sometimes you will still run into the limit and it will be required.

I do wish that Twitter would up their ante too. Maybe not by changing the 140 char limit itself, but maybe by supporting #hashtags so they don’t “take up the room” and instead get moved down below to the metadata layer etc.

Six connections per host

Yay! The 2 connection limit has been so painful for rich Ajax development, especially when you get into advanced work like Comet. This small change is going to be huge.

Connectivity Events

Connectivity events allow websites to check when the user is connected to the network and receive notification of connectivity changes.

This is fantastic. A lot of developers want this functionality, and we have held off implementing it in Gears as it is actually quite tricky to do correctly. Having a version of this in the browser will be great, and Gears applications can leverage it.

DOM Storage

The simple storage for offline applications. I could see someone writing an app that uses DOM storage for simple cases, and Gears for the more advanced (SQL vs. name/value pairs).

Cross Domain

Cross domain is actually going to happen in 2008, which is very exciting indeed. By jumping in we can iron out the issues and end up with a real mashup world that is more than read only tools. I am assuming that this is also using standards such as postMessage.

Cross-domain communication is an integral part of AJAX development
and mashup Web applications. Internet Explorer 8 includes two
features to help you build cross-domain communications that are safe
and easy to implement:

• With Cross-domain Request (XDR), developers can
  create cross-site data aggregation scenarios. Similar to the
  XMLHttpRequest object but with a simpler programming model, this
  request, called XDomainRequest, is the easiest way to make anonymous
  requests to third-party sites that support XDR and opt in to making
  their data available across domains. Three lines of code will have
  you making basic cross-site requests. This will ensure data
  aggregation for public sites (such as blogs) will be simple, secure
  and fast.
• Cross-document Messaging (XDM) APIs allow
  communication between documents from different domains through
  IFrames in a way that is easy, secure and standardized.