Bletchley Park did not just decrypt messages, the contents had to be analysed
Even when decrypted and translated, most intercepted messages did not make immediate sense. The contained acronyms and abbreviations, and often referred to information contained in other messages, or already known to the recipient. All of the information in each message was carefully collated, and recorded on index cards. These cards built up into a vast catalogue of enemy units, places, individuals, ships, aircraft, new items of equipment, and other significant details.This allowed the codebreakers to understand the full implications of a message, and build up a wider picture of enemy activity.
In turn this knowledge also helped the Codebreakers to decide which messages were most important to intercept, or to decode each day. With thousands of messages passing through the various huts this was vital so that nothing important was missed. In the case of Army and Airforce messages this analysis would help in the drafting of the signals sent out as ULTRA, which often contained information from more than one message.