IIUC
In [247]: df['count'] = df.groupby('kind').transform('count')
In [248]: df
Out[248]:
kind msg count
0 aaa aaa text 1 3
1 aaa aaa text 2 3
2 aaa aaa text 3 3
3 bb bb text 1 4
4 bb bb text 2 4
5 bb bb text 3 4
6 bb bb text 4 4
7 cccc cccc text 1 2
8 cccc cccc text 2 2
9 dd dd text 1 1
10 e e text 1 1
11 fff fff text 1 1
sorting:
In [249]: df.sort_values('count', ascending=False)
Out[249]:
kind msg count
3 bb bb text 1 4
4 bb bb text 2 4
5 bb bb text 3 4
6 bb bb text 4 4
0 aaa aaa text 1 3
1 aaa aaa text 2 3
2 aaa aaa text 3 3
7 cccc cccc text 1 2
8 cccc cccc text 2 2
9 dd dd text 1 1
10 e e text 1 1
11 fff fff text 1 1