MSN lists sites in the following order (not all sections apply to every keyword):
1. Featured Sites (this section seems to be at top of first page only)
2. Sponsored Sites (this section seems to be at top of every page - with different results on each page)
3. Web Directory Sites (Looksmart directory sites)
4. Web Pages (Inktomi results)
See the "About" link next to the section heading in MSN SERPs for more info on each section.
I think there are more sections that I didn't list.
> So, as you might already know, submitting your
> site to Inktomi won't improve your position in
> MSN for your main keyword.
To elaborate on this previous comment of mine - which applies only to your specific situation. Say, for example, your page is ranking #15 for your main keyword phrase in the Web Directory section of MSN Serps (due to your inclusion in Looksmart).
Doing a paid submission (or getting a free spidered page) in Inktomi will add your page in the Web Pages section - which is below the Web Directory section. So probably no point in doing this.
> Any suggestions for MSN optimization?
Not a clue. I do some basic optimization for Google (title, <h1>, include keyword on page, etc.) but no specific optimization for MSN. Between my Looksmart listings and free Inktomi spidering, my MSN traffic is about 50-60% of my Google traffic. (My site has something like 2000 pages and I'm currently getting about 4000 unique visitors/day on weekdays.)
What works for Google seems to work for MSN for me. Oh, except the Inktomi results in MSN (the Web Pages section) do display the meta description tag, so I think it might also be used in ranking the pages.