Selected answers from the Dumb SEO Questions G+ community.
Casey Markee: Stop words are filtered out by Google for most queries. Yoast has a good overview that is worth reading on the matter:
Alan Bleiweiss: What matters most is when integrating keywords into any data field, URL, or content that humans can see, it`s critical to ensure it is readable and makes sense from that perspective specific to that data field, URL or content set. So while there`s no need to inject stop words into page Titles or URLs, given that these are accepted to be readable historically without them, it`s critical to include them in content if that content is to be respectful of the human mind.
Gerry White: I’m not sure stop words are filtered out so much as intelligently handled, otherwise Will I Am would be effectively invisible to Google... but yes, consolidation of keywords where the variant is a variant of stop words is often wise ...
Michael Martinez: As long as Bing and Google support exact match search you should include the stop words. People can and do search on phrases in quotes.