Very often it becomes easy to miss that distinctive pink lettering while you're working the auction house, grinding archaeology with the music playing or just not paying attention. Amidst the endless Thunderfury spam and guild advertising macros of most servers trade channel, a whisper can blaze through your chat box as if it was never even there.
Other times, you may be forming a PuG for an old Transmog/Mount run and get multiple whispers at once from people interested in tagging along. And how many times have you had multiple conversations going at once with different people, but had trouble keeping track of it all? Enter WIM.
WIM or WoW Instant Messenger, is a fairly simple addon, but it's simplicity is its beauty. It does little more than take your whispers and fly them out into their own seperate window. It doesn't seem like much, but it's a small change that has huge implications. By having each conversation in its own box allows you to carry on multiple conversations with ease. It also acts as sort of a voice mail program for when people whisper you while you're AFK since the whisper won't get flooded out of your chat box by guild chat, trade spam or group messages while in a dungeon.
I've had WIM installed since the first time I saw it back in the early days of Wrath of the Lich King, and it's become one of those Addons that I simply cant live without anymore. It never fails or breaks, it never clashes with other addons and works seamlessly with other chat modifications like Prat or Chatter. It's been my voicemail service, my Jewelcrafting order queue when I had 7 people lining up for cuts, it's helped me form pugs and keep in touch with old friends from other servers.
If the default Warcraft-themed skin isn't for you, there are several other options you can download and try out as well. I've been enjoying the cleaner look of the WIM_ElvUI skin for some time now.
Seriously, give it a shot. You may never go back.
Download WIM here: http://www.curse.com/addons/wow/wim-3