I just wanted to ping Doug to see if there are any updates on the performance of signals. I also noticed pretty drastic memory performance. Although I haven't benchmarked it thoroughly, I decided to rip out our systems current observer pattern and replace it with signals. For our more ubiquitous app, the memory consuption rose from 110 MB to 350 MB. Even after lazily instantiating Signals through scoped_ptr so they only exist if their specifically connected to, the memory consuption was still at 240MB. (This is all using boost-1.31, gcc-3.3.2, Solaris 9). While I try to figure out where all this memory is being used: Has anyone had any experience with using numerous signals in a large system and found any technique for reducing the impact on memory? Thanks, Neal