MSN / Hotmail users receive more than one billion pieces of SPAM mail each day. Due to this fact, microsoft has implemented a new content filtering technology called SmartScreen. This machine-learning technology presents the most challenging content filter in use by any of the top ISPS. It's recommended that, changing text (that may trigger the smartscreen filter)into images — .jpg or .gif graphics. make sure that you maintain a balance of 50% text, 50% graphics in your message. Common words and phrases that are filtered include, but are not limited to; “unsubscribe” “privacy policy,” “offers,” and similar words and phrases. another challenge with smartscreen is that it discards messages that fail to pass its filter. No bounce reply is sent to the sender. microsoft also employs technology from commercial blacklist provider Brightmail to filter junk email.

-- Listrack