Hi,
Messages and Chats refers the the Storing of Conversations (iMessages) and Chats (Buddy List connections) that you elect to Save.
Where does Skype save it's chats to ?
Prior to Mountain Lion iChat Saved chats were in a folder called iChats inside the Documents folder of the Logged in User.
Path = Hard Drive Name/Users/(your account name)/Documents/iChats (Or ~/Documents/iChats)
Now Messages Saved items are stored in ~/Library/Messages/Archive requiring the specific search of something in the ~/Library, which is not normally searched.
7:55 pm Thursday; October 10, 2013
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.4)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously