Whence Comes The Odd Whitespace?

Confessing more than just a bit of ignorance about listservers, 
please some one tell me why the white space appears in these 
Subject lines when the mail is distributed that aren't there 
when it is posted.  In this case, between the s and i in inside?

RE: [xml-dev] What is the rule for parsing XML in a namespace ins ide HTML?

Wouldn't that hose the subject thread?

len