I think you could be competitive with the other search providers if you focused on a specific topic (i.e. comp scie only). You might be able to eventually provider different portals for each field, too.
Thanks. Currently we do focus on computer science, electrical engineering and math areas. There is a lot of overlap between these fields, so it makes sense to group them.
As for other domains, we do plan to add them later, and as you point out, having portals or a good way to separate them is a good idea.