WordPress : Explain Plugins & Theme string value in database

The value is a serialized php array. Further explanation is not really WordPress specific, but here you go — the ‘s’ is the length of the string representation of the succeeding array element (the length of the string in quotes). I.E. in

a:2:{s:12:"twentyeleven";s:7:"/themes";s:9:"twentyten";s:7:"/themes";}

the “12” in s:12 represents the length of twentyeleven.