Sproose is an alternative search engine which shows you organic search results derived from all the major search engines like Google and Yahaoo, but then adds a twists by allowing voting for pages that you like.

This allows you to not only fine tune and create better search results, but you also get plugged into a network of web sites that have been prioritized for you by other users from their voting as well.
Some people like to draw comparisons to Digg because of the voting system, but I’d like to think of it as del.icio.us search with organic results built in.

Challenges:

Currently the biggest challenge for Sproose is the lack of community participation. Most search terms I tried had few user recommendations if any. The good news is that whatever it lacks in participation, it makes up with organic search results - which means you still get quality search results in many cases so far.
Still - The biggest drawback here would be that you only need very few votes to influence placement of a site in the search rankings, thus those sitting at the top of the pile with a few votes may very well be the ‘choices of a few’ rather than the ‘wisdom of a collective’.

To help increase awareness, Sproose has also recently launched a site widget where once installed, visitors to a page can remotely vote for it to increase their ranking in the Sproose search engine index.

Conclusion:

Despite it’s challenges, Sproose looks to me like an alternative search engine to keep on the list when Google doesn’t give you what you want.

At the very least, this is an interesting experiment in search, and I’m rooting for them to succeed.