Y!M-capable client

Haiku is in real need of a Yahoo Messenger client. BeY! doesn’t work in Haiku and the IM Kit has been abandoned and has versions only for Zeta and BONE.There is no yahoo messenger client for Haiku at this time, and I could really use one. Meebo is not an option for me.

Once Haikuware comes back up you should search for Caya. I’m pretty sure it handles Yahoo.

it does indeed. I use it all the time.

Yes, Caya supports Yahoo, it was my latest work on Caya before gsoc. Stability is good, but i had some problems with the states so you may see a “Online” user as “Away” or similar things…but since it has some problems, the addon is not included in the official distribution and it should be compiled by the user.
The file linked above is a “stable” version of Caya (without yahoo, to install it unzip in /boot) :

www.bluehq.altervista.org/caya-0.1.0-prealpha-x86-gcc4-2011-04-09.zip

and this is the latest svn version of the yahoo plugin (copy the file in /boot/apps/Caya/protocols) :

www.bluehq.altervista.org/yahoo.zip