The article points to
this link for the search engine. I did a search with a small paragraph copied from a paper and found too many results with different scores (it doesn't explain what these scores mean). It didn't tell anything decisively if the text is copied from any source, which is expected from a plagiarism tool.
Secondly, the
About page doesn't talk plagiarism at all. What it says is:
"eTBLAST is a unique search engine for searching biomedical literature. Our service is very different from PubMed. While PubMed searches for "keywords", our search engine lets you input an entire paragraph and returns MEDLINE abstracts that are similar to it. This is something like PubMed's "Related Articles" feature, only better because it runs on your unique set of interests."
However, I must say that the results did give lot of interesting related papers in the same subject which is not easy to find with keyword search. To me, it looks more like a search engine where you can search using a paragraph instead of keywords, which is quite impressive in itself. The site also offers few nifty features such as "Find an Expert" and "Find a Journal" which should be useful for research professionals. I also found the citations page to be quite informative. Since this service is free with API's available, it can be a great source for creating mashups.