Sales resource for self-published writers

I can't vouch for this service, but it is new, and it is free--which means that if you have a self-published book, you have little to lose. Basically the site is a database that gathers information on your book and its sales record. The idea is that traditional publishers seeking to buy the rights to a "proven" title (i.e., they don't need to invest as much money in creating a buzz) can search the database, find your book, and make an offer to you for the rights.

From their website:

The Publetariat Vault provides a new kind of service to self-published authors: the opportunity to get your indie book in front of the publishers and producers who are seeking proven books for low-risk acquisitions. Publishers can:

Find independent literary material that is already proven in the marketplace

See actual sales data, and know if the work already has traction

See reader reviews from bookseller sites, reader communities like Goodreads, blogs and elsewhere

Search by genre, topic, keyword, recommended reading level and more to find the kind of content you want to acquire

See author platform pieces, buzz, publicity and more, and know if the author will be an active partner in promotion