Let's put aside Yahoo!'s FUSE (Find, Use, Share, and Expand) strategy for the moment and look at what the company is doing with vertical and horizontal search (horizontal search being, well, search).
Yahoo! recently launched a specialized Travel site to go along with its other vertical sites and content plays. Also, the HotJobs meta-search/vertical search expansion got a lot of coverage. In fact, that gray-blue box near the top of the Yahoo! home page is a list of verticals. And Yahoo! just launched a bunch of health blogs.
Some would also consider Local a vertical, but it's only a vertical if vertical means specialized content (which means almost everything other than general Web search is a vertical).
Through its verticals, Yahoo! is building lots of content depth and feature richness around that content. Yet that isn't an alternative to a general or horizontal search strategy; it complements it. (Very few folks can play in the all-too-competitive general search arena, which is partly why there's a boom in verticals.)
Comparing search and the vertical experience — in the comparison shopping context for example — Kelsey Group-ConStat consumer data from March of this year show that search engine usage is much farther away in time vs. shopping engines from the transaction (which indicates where the consumer is in the buying cycle when using the sites). From a direct-response standpoint, that's why verticals matter. Although highly effective branding certainly can occur in a vertical environment — think cars for example.
Accordingly, the parallel market trends toward meta search/aggregation and verticalization (to provide more targeted inventory, leads closer to the transaction) is mirrored within Yahoo! and in the HotJobs move in particular.
Notwithstanding all the hype surrounding verticals, I continue to believe that verticals will not take over from the main search engines. That's because consumers fundamentally don't want to go to dozens of different sites — as information proliferates, they want reliability and convenience. This augurs well for the big search players (one-stop, trusted brands). Traffic data would seem to bear that out.
But to now speak out of the other side of my mouth: If a vertical directory or search provider can establish a solid brand, backed up by a great user experience, consumers will go there directly.
Related: Danny Sullivan's analysis of new Nielsen search market-share data.