I do think this is a sad day, as the project was, to my knowledge, a unique one. For anyone that doesn't know, the IMSLP was attempting to create a vast library of Public Domain sheet music and scores to substantial works, and make them available for download for the everyday user in a digital format. This was an absolutely amazing website for musicians doing research, as they often had multiple editions of pieces scanned into their libraries, which were vast and contained a multitude of works by a multitude of composers.
I only hope that this legal action is resolved quickly, as the IMSLP was dealing solely in public domain works, which is entirely legal.
As an aside, I found their point fascinating: Why is the MPA of the UK (or the US, or any other country for that matter) more willing to push the works of modern composers? Is it simply considered too high risk a venture in a market that leaves little room for wide capital gains, and certainly little reward for failure? I guess they're not willing to speculate in something as subjective as musical taste. But it's true, it is sad that so many companies are hell bent on making a profit off of composers long dead, whose works have long ago entered the public domain. The industry, as it is, is resisting an inevitable change. We may not like it, and it may not be pretty, but it's going to happen. You can either ride the wave, or drown in its undertow.