Siri has been a huge succes. It helps you to make reminders or setting up appointments. The downside of Siri is that you have to be connected to the internet via 3G or WiFi all the time. Siri streams your voice to Apple for processing and then sends the results back to you. That’s why the folks at arstechnica.com investigated how much data Siri uses.
Arstechnica performed different queries trough Siri and tracked how much data each query used. They found out that local tasks, such as setting an alarm or adding a note, use 36.7KB on average. Tasks that require lookups online, such as google searches, use an average of 94.72KB per query. They also tested text dictation. An e-mail with 40 words used about 109KB, another e-mail with 15 words used about 36KB.