Follow up date!
There is "start date" and "finish date" but no "follow up" date. This would be EXTREMELY helpful when creating your activity to see to indicate when this needs following up. There are many cases where i create a task then do something on it, like send a mail or do some work on a document and wait for someone to review or add something on it. This is where the follow up button would be really helpful as it reminds me that i need feedback or a responds from that person. it would go without saying that a new feture of being able to search for a specific follow up date in the filter is also very good feature.