Quantity of Digest Issues

[Robert C. Lightfoot]

Dear Testing Community:
     I am new to Fedora Testing so this may be a newbie or repeat 
question and if so I apologize.
     I was under the impression that the Test-Digest was a daily 
mailing.  Is any one else puzzled or concerned like I am about receiving 
4 or 5 digests on some days.
      If each had 12 or 20 topics I could see the need to split them up, 
but the count is 4-1-4-3 for issues 62-65 all with an issue date of 
2010-01-27 for example.

Sincerely,
Bob Lightfooot

P.S. - Just curious if anyone can shed light on why and when digests are 
generated.