Another way to copy/ add links..

You can copy the URL (highlight the full text & right click to select copy & then paste it in a post.
URL- the http://
& / or
www. (whatever site name is ) .com , .gov. or .org part -usually in the top section above the web page


http://www.ssa.gov/retire2/credits.htm

Some will just have only the www. & some will have https:// which is usually for secure log in pages