FACTA is not in this context the Fabricated Access Covers Trade Association or the Fair and Accurate Credit Transactions Act, but a tool from the National Centre for Text Mining at Manchester, which uncovers associations between biomedical concepts mentioned in Medline articles. Enter a search term, and you will be presented with lists of associated concepts covering genes, diseases, drugs, and other things (which things are shown depends on the tick boxes that are selected when you search). You can then click to see "snippets", which highlight your search term. I tried it with HFE (the gene associated with hemochromatosis, the example from the Gene Gateway Workbook, described in a previous posting) and got 1564 hits connecting it with the disease.
Any of the associations are links so that you can see their own associations.
FACTA is described in a open access paper in Bioinformatics:
Yoshimasa Tsuruoka, Jun'ichi Tsujii, and Sophia Ananiadou. 2008. FACTA: a text search engine for finding associated biomedical concepts, Bioinformatics, Vol. 24, No. 21, pp. 2559-2560 (there is a link on the FACTA site to this).