When visited with w3m I got spaces breaking words frequently.
Is there any justification to use complex html to control intra-word spacing for a web page?
Those are soft hyphens, which supplement the crappy hyphenation support built in to most browsers. w3m should probably just ignore them, but it looks like your version is broken[1].
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=441934