|UI location||File > Export > Selected|
|Current version download||https://raw.github.com/dairin0d/export-selected/master/io_export_selected.py|
Hit CtrlAltU to load up the User Preferences (or use the File menu and click Save User Settings). Click the Install Addon... button at the bottom, then navigate to your io_export_selected.py script.
Next, checking the little box on the right of the addon entry in the list. If, for some reason, you have a hard time finding it, you can search for Export Selected or click on the Import-Export button on the left.
If you want to keep this addon available at all times, follow the above steps on a fresh .blend (CtrlN to create one), then hit CtrlU at this point. The next time you run Blender you won't have to repeat the above.
When installed, it will add a submenu "Selected" to the Export menu, where the available formats would be listed.
Adds an option to export only selected objects for every registered exporter. The addon also gives you an option to export the objects to a separate .blend file.
By default children of the selected objects are exported too (the "Include Children" option).
Besides the selected, you can also choose to export visible or all objects in the scene, and/or to limit export only to certain types of objects.
For PLY format, all the selected objects would be exported as a single mesh.
Same as with other exporters.