before starting pidgin
             total       used       free     shared    buffers     cached
Mem:       2062860    1928912     133948          0      18168     589872
-/+ buffers/cache:    1320872     741988
Swap:      1020116     123928     896188

while pidgin is running
             total       used       free     shared    buffers     cached
Mem:       2062860    1938840     124020          0      18264     590556
-/+ buffers/cache:    1330020     732840
Swap:      1020116     123928     896188

after closing pidgin
             total       used       free     shared    buffers     cached
Mem:       2062860    1930444     132416          0      18308     590844
-/+ buffers/cache:    1321292     741568
Swap:      1020116     123928     896188