The default user interface in Microsoft Office SharePoint Server 2007 only allows you to schedule audience compilation once a day but what if you want to do this multiple times a day? Luckily there is a workaround.
Behind the scenes audience compilation uses audiencejob.exe which you find underneath c:\program files\microsoft office servers\12.0\bin\. To find the correct syntax just type audiencejob.exe this will give you something like
AudienceJob.exe <Application Id> <Command> [Crawl Type] [Audience Name]
Application Id: Guid corresponding to Search application
Command: 1 = Start, 0 = Stop
Crawl Type: 1 = Full, 0 = Incremental (default = 1)
Audience Name: Specific audience to compile (default = all)
Application Id for SharedServices1: be1cf629-000b-4af3-8f6c-dfc3c96563a0
C:\Program Files\Microsoft Office Servers\12.0\Bin\audiencejob be1cf629-000b-4af3-8f6c-dfc3c96563a0 1 Full all - will recompile all audiences from scratch.
You can easily use windows scheduler which calls audiencejob.exe to create a scheduled job which runs multiple times a day.