The Numbers Without the Form

The first thing I did was to write down the numbers that Feedburner provides. I basically tracked the number of email subscribers on my three blogs, for four consecutive Mondays (four weeks were used because that was the longest period that I could obtain the breakdown for email subscribers).
DailyBits.com

• Monday of July 07 = 109 email subscribers
• Monday of July 14 = 112 email subscribers (+3)
• Monday of July 21 = 112 email subscribers (+0)
• Monday of July 28 = 114 email subscribers (+1)

As you can see the average weekly increase of email subscriber was 1,3.
DailyBlogTips.com

• Monday of July 07 = 932 email subscribers
• Monday of July 14 = 950 email subscribers (+18)
• Monday of July 21 = 966 email subscribers (+16)
• Monday of July 28 = 979 email subscribers (+13)

On this second case the average weekly gain of email subscribers was 15,6.
DailyWritingTips.com

• Monday of July 07 = 4986 email subscribers
• Monday of July 14 = 5040 email subscribers (+54)
• Monday of July 21 = 5129 email subscribers (+89)
• Monday of July 28 = 5153 email subscribers (+24)

For the third blog the average weekly gain of email subscribers was 55,6.