Here is the tweet analysis for the Tru London 5 recruitment unconference. The report covers a maximum of 1500 tweets which explains why there might be some missing. That said, if all tweets were included then the reach would be greater. And this analysis give a good picture of the Twitter activity.
This report is not only useful for checking out the Twitter stream and reach of the event, it is also good to see who the influencers are in helping amplify the event and also who is engaging with the event.
For those interested in services for measuring hashtags/Twitter streams, I have been using Tweetreach for one-off reports. The monthly pro-reports provide better reporting due to the fact they track tweets as soon as you let them know you need them to be tracked – the reports I use are retrospective ie you purchase it once the event has taken place.
Hashtracking also provides similar services. It is still in beta but I am aiming to try it out once I can get in.