How many times have you sent an email to someone, but forgotten to also send an all-important attachment? If you're like most people, you've most likely done it a fair number of times. CatchAttach (€2) aims to make sure you never do it again--in Outlook, at least--but only partially succeeds at the task.
CatchAttach integrates directly into Outlook 2007 or Outlook 2010, so that you don't need to run it as a separate program. It looks for keywords in any email you send that indicate you plan to include an attachment. By default, the only text it scans for is the word "attach," although it will also look for "attachment," "attached," and so on, because those words contain the text "attach." If it finds a match for the text, and sees that there's no attachment, it warns you that there's no attachment. You can then send the mail as is, or attach a file.
It's extremely easy to add your own key words or phrases. You can also change the text that CatchAttach displays when it finds out that there's no attachment.
CatchAttach is only moderately useful, though, because it's not likely that every time you send an attachment you will include the text "attach," or any other specific text in your message. So yes, it will flag some instances in which you forget to send attachments, but not necessarily all of them.
In addition, CatchAttach is guilty of intense nagging until you pay for it. Until you pay for it, every time you send a message, whether the flagged text is in the message or not, it nags you to register.
If you do pay for CatchAttach, expect it to find some but not all instances of forgetting to send attachments.