Trillian itself was a proprietary knockoff of Gaim, which later became Pidgin. Surprisingly both Trillian and Pidgin are still alive and in use today.
EDIT: Decided to read a bit on the Wikipedia pages and it was a bit less cut and dry than I made it seem. History’s interesting.
On the one hand I support this wholeheartedly. On the other, this may be the fuel finally needed to push a Linux phone or two more mainstream. I’m conflicted.