We just now pushed out Foxmarks 0.90, a beta version that contains one small (but, we hope, useful) change. We fixed Foxmarks so that it no longer ruthlessly tramples over your favicons, which was unsportsmanlike at best. We still don't yet sync your favicons, as that's a bit more work. But at least now we're following the principle of "do no harm."
Please take it for a spin and let us know how it works for you.