Added two sites to the list, Bukisa under the "Passive Income" section, and Words of Worth under the "Sites which Pay Upfront Section"
Personally, I don't like Bukisa, and I have indicated so in the site description on the list itself. They have been around since late 2008, which does mean that they are relatively new as a content site. I have to say that they are actually better than when they started out, when they didn't care what you published there as long as it was 250 words. They, however, still have a long way to go.
Words of Worth is a UK site set up in 2007. You enter into a contract with them, where you promise to deliver 10 to 80 articles every month, depending on the contract, and they promise to pay you £250 monthly.
Contracts typically last for 12 months, and they do require you to give a month's advance notice should you decide that you want to quit. You are not limited to one contract and can choose to apply for a second contract with them, though they will only consider it if you have been writing for them for some time.
Note that they also recommend that you schedule your articles to be published evenly throughout a month e.g don't publish 40 articles all on the last day of the month if you have a 80 article monthly contract. According to thier guidelines, article length should be from 200-500+ words.