This tool takes some text (in theory the abstract of a paper you're thinking of posting as a preprint), sends the text to JANE which recommends journals that publish similar content, then looks up each of those publishers in ROMEO to find out their preprint policies. Those publishers which are happy to accept papers already available as preprints will show up in green.
This tool performs a comparison of the semi-automated/semi-manual matching of MeSH terms to papers in PubMed (I believe they're suggested by UMLSKS then manually curated) with the similarly auto-manual detection of Wikipedia terms in abstracts by GoPubMed and the corresponding categories applied to those papers in Wikipedia. Rattle Research and Chris Sizemore at the BBC have done lots of interesting work on this kind of thing with news articles.