How do I organise my chats?

Hi all, I don't know if anyone else has this problem on second life but i always get to meet people,adding them to my friend list and end up not finding them in my friend list next time I login. They are in there but I don't seem to keep remembering SL names. It takes me up to a few days of chat before i will link a sl name to an avatar. Is there a way filter your friendlist on latest time you had contact?

Unfortunately there is no way on the friends list to do any kind of filter.

To be able to sort by friends, acquaintances, business contacts, etc. would be very nice but not available. Some people use the calling cards for those purposes but I just ignore and eventually delete them.

You should also have their callling cards in your inventory. Not sure if this works on calling cards as well to be honest, but if you sort your inventory by date the last calling card you received should be at the top of the folder.
Won't tell you last contact but will tell you latest addition to your list.
Logging IMs with time and date stamp will tell you latest contact, but not in chat. Chat logging i don't know about.
Also try using the my notes page in people's profiles if you have a hard time keeping track of who is who.
If all else fails, pen and paper might work

Yep, use the notes page in profiles. I always try to make a couple of comments, so I know who I'm looking at until we get to know each other (or so I know we've never spoken since when I have a Friends List Purge!)

An added bonus is it's fun to check back when you've been good mates with someone for a while, and read the notes you made on your first impression!

The most useful thing I find is just being a bit blunt about friendship invites and saying I only add friends when I've known someone a wee while*. I swap calling cards - but if we never speak again it's not another 'mystery name' on my list. If we hang out enough to make 'friends' then we'll probably stay that way!

(*Havng said that I'm still caught off-guard and have to check the names I don't recognise quite a bit. And the other day I accidentally added someone whilst camming around in laggy weather, so hey..)

Everyone you chat with is logged in the chat log.
If you have chat login enabled, SL adds all of your chat into a log file. On a windows machine the file is found in:

C:\Documents and Settings\USERNAME\Application Data\Secondlife\AVATAR_NAME

USERNAME is the name you are using on your machine and AVATAR_NAME is the name of the Avi you want to look at. SL creates a separate folder for each avi so if you have alt's you will find several folders here.

If you have Log IM to Chat enabled, then SL will create a separate log file for every person you IM with. These are in addition to the chat log. This log file will have the name of the Avi you were speaking with.

Note: In their wisdom LL put the data into the The Application Data folder, which is a hidden folder, so you cannot get to it through My Documents. You have to browse the file stricture to get to it. Why they made it so difficult to get to the logs is beyond me. Putting the SecondLife folder under the logged on users My Documents would have been easier.