Goxml is a new search engine for indexing XML content on the web. It has addressed the context problem in a neat way. For example, enter 'Shakespeare' in the search field and hit the search button. You're then asked to supply some context, which is essentially the tags around the word Shakespeare, such as AUTHOR or NAME. If you don't supply the context the search engine will list out the contexts it knows about for you to click on. This solves one difficult problem but the biggest obstacle is just the nature of XML documents. Search engines for HTML make sense because there is a very well defined linking mechanism to discover other HTML documents. XML doesn't have that and I'm not even sure that an XML search engine can ever survive given that it relies on manual entries.