What does the expression "a media splash" mean? Is it something like a reference or mention appearing in the media?
A "media splash" is noticeable coverage in news media -- newspapers, TV, radio, online outlets, etc. Here's a headline from The New York Times: Beyond Publish or Perish, Academic Papers Look to Make a Splash. It's about academic economists who want their papers reported on for a general readership instead of having them restricted to an audience of fellow professionals in technical journals. ("Publish or perish" refers to the necessity of publishing work in such journals to get tenure at a university: no publications, no tenure, no career.)
A medial splash is generally considered good publicity.