If you find your layouts break really badly in IE8, and if you then find that that is because IE is rendering the page in Quirks Mode, and if you use drush you find this  UTD-8 byte order marker appears while commands are executing... all of that is because Semantic Similarity has files with a byte order marker, which ends up printed before the doctype and confuses Internet Explorer.
Don't spend ages debugging css and looking for print_r statements like I did, use the commands here in the Semantic Similarity folder to remove the  from the files. (if that link breaks, find . -type f -exec sed 's/^\xEF\xBB\xBF//' -i.bak {} \; -exec rm {}.bak \;
)
Comments
Comment #1
benoit.borrel CreditAttribution: benoit.borrel commentedRemoved BOM in files.
Comment #2
benoit.borrel CreditAttribution: benoit.borrel commentedI fixed the issue in 6-x.1.x-dev as well.
Comment #2.0
alanom CreditAttribution: alanom commentedRemoved comment suggesting it's a dead module - glad to see it's still going!