Strange Export Sizes (exported files seem too small)

I recently exported a few different versions of a shoebox i made earlier, complete with textures/mapping, and noticed how small the exported files were.
All packed and ready to go, the .blend file was 2.3 mb, but it only turned out a .3ds file of 4kb, .fbx was 64kb, .lwo was 4kb, .xsi was 108kb, and exporting to wavefront .obj turned out .mtl and .obj files of 1kb each.

If i try to re-import any of said files, nothing happens. Is there something i could be overlooking?