Hi Benjaloo,
we are open to any suggestions regarding this issue. While we are concentrating on the Windows platform at the moment, we still want to provide support for other OS as much as is possible for us. At the moment there is no "common" way to store tags for different search engines, many of them do not support tags at all. Besides images (JPEG EXIF) and music (ID3 tags) most file formats do not support storing tags inside the document itself.
We will try to provide some basic support for search engines as development continues. I cannot however promise how much "cross-platform" this support can be. But be ensured, we will try our best.
Best regards,
Martin