Thanks for your inquiry. ~ We appreciate your patience :-)
That is a serialized array of First Payment Dates, as Unix Timestamps. s2Member® keeps a record of the First Payment Date and Time at each paid Membership Level.
a:3:{s:5:”level”;s:10:”1337166521″;s:6:”level1″;s:10:”1337166521″;s:6:”level2″;s:10:”1350867691″;}
Please see: Knowledge Base » Import (or Mass Update) Users -› First Payment Date(s)
array(
'level' => '[timestamp of first payment date, regardless of level]',
'level1' => '[timestamp of first payment date at level #1]',
'level2' => '[timestamp of first payment date at level #2]',
'level3' => '[timestamp of first payment date at level #3]',
'level4' => '[timestamp of first payment date at level #4]'
)
In your example, some of these Levels are missing. That’s normal. It indicates that a particular Member has never had access at some of the higher Membership Levels.
As Eduan pointed out, you can also export your CSV file in a more readable format, so you don’t end up with a serialized array — if you prefer. This is optional of course.