The ?'s are due to the set character set on your forum not allowing the character; in this example your users seem to be attempting to use the reverse apostrophe character commonly used in Microsoft Word, and that character is not a UTF8 character; simply go to the generic language file and change it from UTF8 to iso-8859-1.
“You will have confirmation tomorrow from the WEC and Le Mans about the entries, and you will have good news a yellow car is inside,†he said of Thursday’s press conference where the FIA and ACO will set the field for the upcoming season.
“We will probably go to test the car in March in Sebring, and then it will become very busy for us after the championship starts.â€Â
The website whom you are scraping RSS content from ( http://www.racer.com ) is delivering iso-8859-1 feeds. Your site is now displaying content as utf-8. You basically need a converter built in to your rss content scraper. I've written just the basics of one in to the scraper you're using.
Download the attached zip file and place it's contents in to your /forums/cache_builders directory.
Any new content will be converted on the fly. Any older content will remain as it was when you first scraped it from racer.com's rss, to use as your own content.
Pro tip - you might also want to add some attribution to any content you're using if you were not the one who created it.