I've not heard of KnowboForm but I'll check it out...
Backlinks are extremely important as many of you have said already but the search engines are clever and the ranking of such backlinks is very difficult to get right.
What you have to do is make sure that the backlink is related to your content and the keywords you choose are related (anchor text whithin the link itself).
This is something that I've spent a lot of time trying to get right on
Add An Image - Online Gallery - Create and Share your own image links - Home
For every post that's submitted the anchor text is used in the meta data and title of the page as well as the backlink to the submittors site.
We also now have free TGP submission which works a little differently to most TGP's - when you post your TGP on our site each image gets a page and a backlink.
The TGP submission page is here:
TGP Submission Form
NB: All submissions are checked manually and we will delete anything that we believe is inapropriate. Hotlinking must be enabled on your server for the initial load of the image.
Add An Image - Online Gallery - Create and Share your own image links - Home is currently growing by over 1000 images per day and we have something like 50,000 pages listed in Google (the site has over 113,000 pages at the time of writing this message).
So, come along and post either individual pictures or TGP's whilst its still free
