MSN
MSN will continue to chase Yahoo! and Google in search. While I am impressed with their beta search I do see that much improvement will be needed. However, in a rush to get it out to the general public, they will push it out of beta too soon and with too many holes. I see soon that after the beta search becomes mainstream it will be hacked and taken over. It will likely come out of beta in the first half of 2005.
MSN will also try to integrate search into more of their desktop products. Desktop search already does search emails and documents, but you have to launch the search from the desktop application. I can see future updates to most of the office line of products to allow you to tap into the desktop search from Word, Excel and Outlook, just to name a few.
Further to this, I see that MSN will probably replace the search built into Windows with the desktop search. Or at least use the technology behind the desktop search to power the local search. With the recent announcement that WinFS is not due to be released for many more years, it only makes sense that something will have to supplement the gap created by a poor local indexing capability.
While MSN won't go the paid inclusion path, I expect to see them to begin to develop their own PPC model by the end of 2005. It will likely be a unique model which no one else is doing (like pay per conversion, rather than pay per click). All you will have to do is install the MSN PPC tracking code on your site, and use their management console to track your campaign. This will be an excellent research tool for Microsoft, and they will be able to learn how people use their search engine, so they can better refine their results.
The others
As much as it pains me to lump Ask Jeeves in with "the others" I feel I must. I do see them coming out of "the others" group in 2005 to establish their own dominant and growing web presence. I think of all the engines, Ask Jeeves will be the one to watch in 2005.
I think we'll see changes in how they display their results. We will see paid ads taking less of the search marketing space on their SERP's with a focus on more organic listings. This will force web marketers to sit up and take notice.
I also see them developing more technology, as they continue to gain momentum from users switching from the big 3 to an alternative.
Essentially, the rest are just that "the others" - and they will make small inroads, but overall the market will still be dominated by Google, Yahoo and MSN, but their dominance of the market, that is the 90+ percent share of the market, will begin to shrink.