I’m glad you enjoyed the article – thanks for taking the time to read it.

1) What is the X-Domain request that is being made? Can it be avoided?

Since I was developing the application on my own development machine and running it using Visual Studio the my Silverlight Twitter application was being hosted on http://localhost. From there the application was making a web request to http://stream.twitter.com. So, the X-Domain request is from localhost to stream.twitter.com. The only time this would not be a X-Domain request is if I could host my application on stream.twitter.com or another sub-domain of twitter.com. So, unless Twitter introduce a hosting service this can’t be avoided.

2) What perf problems are you seeing?

The application was performing reasonably well although there were occasional CPU spikes. I’ve not done a massive amount of analysis on the application since it was just created for the MSDN article. You can see me checking out the CPU in the video. If I left the application running for a reasonable amount of time it would appear that the performance would degrade. My example only connected to the sample feed which only sends a small proportion of the Firehose feed that Twitter will soon be making available to everybody (as I mentioned in my “How does Google real-time search work” post). In addition, the work I was doing with the data was not very complex – all I did was insert it into an object that could be bound to a DataGrid. I think it’s unreasonable to expect a browser plugin application to be able to consume the entire Firehose Twitter feed and still perform. In addition, a user wouldn’t be able to analyse all this real-time data. If you are going to write a Silverlight RTRIA then you should:

• Keep the amount of data your application is consuming to a reasonable level
• Ensure the format of the data being streamed to your application can either be used directly or is easily transformable into a usable state e.g. deserialised
• Push work onto a non-UI thread as soon as possible to allow the UI thread to continue to ensure the UI is responding to user actions

If you want to do a lot of data manipulation, for example consume data from two real-time data feeds, then it’s probably a good idea to do your data manipulation on a server and push this manipulated data to your Silverlight RTRIA from your own real-time server.

Interesting article. A great example on how to access twitter.

I had a couple of questions:

1) What is the X-Domain request that is being made? Can it be avoided?
2) What perf problems are you seeing?