I just tested that theory and SilverBear is 100% correct. It affects things when you use quotation marks in the search.
Example: search for "Chasing Colours" using the quotes. No results. Search without quotes and it comes up. That is because when you search using the quotes it is looking for
Chasing AND
Colours, but there is part of a
bold tag in there. It looks like this to the search engine:
So no match.
Anyway, I'll forgo using bold for the matching word(s) or letters and do CAPS instead (the search engine doesn't care)