If you have been struggling to generate revenue from your site ( despite having decent traffic), you should try multiple sources to advertise .
Apart from context based text advertising and referral ads, you can also try tying up with niche advertisers related to your line of blogging. These niche advertisers pay premium rates when compared the text based contextual advertisers. You can also try getting some local advertiser for your site/blog.
Although going with multiple advertisers can boost your income, it is important to check the terms and conditions of ad providers wrt multiple advertising before you enroll.
if you do that MSI is the way to go!! (MSI ~Multiple Source of Income )