How does the plugin help in load time?
Social Media buttons are heavy resources. If they are not implemented properly they slow down your website. So they should be loaded intelligently. They should also be loaded only on pages Lockers are present.
These buttons should not be loaded on all pages. So only pages with Lockers on will have some impact on load time. This is exactly what this plugin does. It only loads the files only on pages social locker buttons are placed.
So your rest of website remains fast as ever. The resources are loaded with intelligence to make sure locker pages also have minimal impact on load time.
How to make my website social?
I have written detailed tutorials on major social networking sites out there. You should read those tutorials. Below is the link to free WordPress course. On this page you will find links to Social Sites for SEO and Traffic tutorial along with other tutorials.
What file formats are supported for download?
You can use any file format for download. Visitors will be able to download any type of file post social action. But I recommend using ZIP file formats. The reason is browsers typically present Save dialog or Download dialog for ZIP file formats.
For other file formats it may open then in the next tab. You can ZIP your files or images and present them as download.