How Do I Track Database Growth?

You can check the chart at the top of Marketing Activities to see the past three months.

Another way is to check your database on the last day of each month.

Another way is to pull a report in Marketo:

1. Lead Performance
2. Group by Created Date: All Time by Month
3. Smart List = Member of Smart List NOT IN "Exclusions, tests, etc" <--block your own team and stuff that doesn't count
4. Run Report.
5. gives you a list.

Note that the day you started marketo or made big changes to your system may have abnormally large values.

I just started work on something similar! Here's what I'm doing

To do the past 12 months, you'll want to start by running a smart list of all leads created before the first day of the month you want to start tracking (e.g. Before 1/1/2014). 

I like Josh's suggestion of excluding your test records and normal exclusions for this. You also have flexibility to include or exclude unsubscribes, bounces, etc, depending on what you want to consider growth (all leads, only mailable leads, etc)

Then you'll want to make a smart list or lead report for each month of newly created leads and use that to show your DB growth each month.

Example:
Smart list 1: Leads created before 1/1/2014: 1500 <-- this will be your base/starting point

Smart list 2 (or lead report): Leads created between 1/1/2014 and 1/31/2014: 150 
January growth: 150/1500 = 10% growth and 1650 total leads at the end of Jan

Smart list 3 (or lead report): Leads created between 2/1/2014 and 2/28/2014: 125 
February growth: 125/1650 = 7.6% growth and 1775 total leads at the end of Feb

Smart list 4 (or lead report): Leads created between 3/1/2014 and 3/31/2014: 200 
March growth: 200/1775 = 11.3% growth and 1975 leads at the end of March

etc..

YIKES! So there is not report for this. Ill plan to spend my entire day on this. Bummer :/