Xerxes is a federated search and ‘saved stuff’ interface that uses Metalib as a broadcast search engine.
Features I have added to Xerxes recently:
- A saved databases/personal quickset feature
- configurable support for Metalib ‘link to original record in native interface’ and ‘link to holdings in native interface’
Features I plan to add to Xerxes in the intermediate future (hard to say how long it will take my so-called ‘plans’ to come to fruition)
- Generalize the ‘saved records’ feature to serve as a centralized ‘saved records’ accross multiple open source and proprietary library applications. (David has the groundwork for this in place, but there’s still significant structure to be built). Include javascript support for dropping into existing proprietary search interfaces.
- Add RSS/Atom feeds to Xerxes search results. (Harder than it seems because it’s hard to get a persistent URL to search results from underlying Metalib engine).
- Create a generalized ‘saved searches’ feature that can work both for Xerxes and also across other applications as a generealized central store. Built on feeds and an OpenSearch data model, so using the above bullet. Hopefully also supporting email-based alerting of new items from saved searches.
- Provide an ISSN-to-Metalib-resource mapping, so the above feature can be used for an alerting service for new content from a specified journal. (David has taken some experimental stabs in this direction).
- Integrate Umlaut into Xerxes, so a Xerxes record detail page has Umlaut services provided directly on the page.
Features I would like to add to Xerxes (but can’t be said to have ‘plans’ for, even for a very loose definition of ‘plans’ as above)
- Integrate the ‘saved records’ functionality (including existing tagging) into one or more shared ‘cloud’-level stores of scholarly ‘social’ citations. SOPAC? Connotea? Something else? Would need to be a shared store that somehow recognizes when multiple records/citations represent the same work, so social data can be properly aggregated. And ideally that works for both monographic and journal article citations (perhaps by combining several services?)
- Add a way to publish a subset of your saved records (by tag?) as a public ‘bibliography’, with appropriate full text/openurl/worldcat registry links for users from any location/affiliation.
Bibliographic Wilderness 
Is RSS/ATOM the only proposed mechanism for getting information out? Have you considered RIS?
It is already possible to get items out as RIS, but you need to first save them to your ‘saved records’ area. (which you can do even if you don’t have an account, in a temporary area). Then you can export from your ‘saved records’ area in RIS (among other options) — everything, everything you’ve tagged/labeled with a given label, or individual items checked off. That already exists.
The RSS/Atom idea is for arbitrary live search results.
There isn’t a good way to do an RIS export of an entire live set of search results. I suppose we could have an RIS export of search results a page at a time, but I’m not sure how much use that would be.