I think the best user experience you're going to get is by giving the user as much information as possible. Throbbers deliver almost no information (just an in

I think the best user experience you're going to get is by giving the user as much information as possible. Throbbers deliver almost no information (just an indication that something is probably happening); progress bars exceed that a bit by indicating a rough percentage of completion and allow the user to estimate time until completion, but users are trained to be suspect of progress bars (who hasn't been at 99% for 99% of the time...). I would give a progress bar with semantics specific to what you are doing (step 3 of 5 instead of 60%), estimated time to completion, and a description of the current step (Submitting search request to Expedia... Filtering results... etc). It can be accomplished a lot of ways, but will likely be more responsive if you push the data. The easiest way I have set up something like this has been node.js, redis pubsub, and socket.io. Requires some reading, but the end result is you can push messages through Redis from your app easily, it will work in all browsers, and you won't have to write very much glue code at all.