As search engines/portals would not necessarily have many pages for indexing purposes, how would one promote one? Obviously not many people search a known search engine for another one I own http://www.yourhotsearch.com and am currently using signatures and some links on PR4-5 pages to try and promote it.
You're bang on that people don't use google to search for other SE's. There are two routes to promote something like that; offline and online. Online, develop as many quality links as you can from relevant sites. I expect if you're here you already know how to market online. That's what you've got to do, except the focus is on traffic development not SE love. Get media interviews or blog interviews if you can. I try and promote mozdex. Prior to my taking on that project the former project owner did a lot of media stuff and promoted opensource. I'm going to continue with the opensource aspect, but ad in some promotion in places like here (where PPC advertisers lurk). I've also got a Canadian search engine. I post that around in relevant places too - places where Canadians hang out. There's a Canadian site similiar to fatwallet that I post to - not directly promoting my site but I try and post meaningfull stuff. As a result, the site has taken some traffic (though admittedly I haven't done a full scale launch of that site). Your search engine also needs a hook. Mozdex, in addition to the opensource aspect, offers a free open search feed - an RSS api anyone can query. Like Google's api, except free and basically unlimited. Places like metasearch engines use the results, knowing that they can do so for free without a 1000 search limit. That another hook that helps get the name out there. Why would someone use me? Well, I've got a free search feed you can use, that's why . Offline I think is where you can make a push too. Ask.com I believe does a lot of TV advertising. I'm feeble when it comes to offline marketing so I can't offer anything of value.