At Acquia, we've launched Acquia Search in public beta today.
Acquia Search is 100% free for now, and here is our marketing pitch:
Acquia Search can be installed as a module on any Drupal 6 site, and enhances a site's search experience with faceted search navigation, content recommendations, and configurable results weighting, all delivered through a redundant hosted service infrastructure.. Put a bit more directly, Acquia Search is simply a great way to supercharge your site's search experience, without having to invest in your own Solr engine and development.
Though we're not sure how long our beta program will last, one of our motivations in providing a free beta is to help figure out the pricing model. There will likely be two main components to our price structure — the number of nodes on a site and the number of search queries. The free beta will allow us to get a better feel for that.
But what about Drupal's built-in search module? This announcement doesn't mean that we'll stop enhancing it — in fact, the Drupal 7 search module already has some improvements over the one in Drupal 6. There's lots of room in the "search" arena, with lots of different use cases, and it is hard for the core search module to compete with commercial-grade search engines while running on shared hosting environments. For a certain class of sites, including drupal.org, Drupal's built-in search is simply not an option, and we think Acquia Search can be a great fit for those sites.
Acquia Search is only possible because of the fantastic work of the many people who have helped make it a reality. The Apache Solr Search Integration project on Drupal.org, for instance, reflects the work of many community members, including Robert Douglass, Peter Wolanin, Jacob Singh, Damien Tournoud, and more. Thanks!
— Dries Buytaert