You do not need to have a website or a blog to be successful with SFI. However, having a website or a blog is more advantageous than nothing at all.
If you have that site you can refer anyone or your prospects to that site where you have a detailed stories about SFI and TripleClicks.
You can also post anything on your own website/blog of any unlimited words regarding SFI advertisements.
But it's not a guarantee, because you can still put your campaign regarding SFI on any other sites that has thousands or millions of visitors coming everyday.
You can also join some groups just to advertise and promote SFI. In other words, even without having your own website or a blog, you can still be successful with SFI.