Hm yeah, the link seems strange so I opened it in a virutal mashine, just to be sure. It redirects you to https://medium.com/bitwalking/bitwalking-begins-24b55a5ff066#.1fxx4lbg1 which really is an article about Bitwalking which then leads you to http://www.bitwalking.com/

It may be legit and sites like BBS and Forbes covered it (links are on bitwalking.com at the bottom). There they describe, you need to walk about five miles: "[...] walkers earning approximately 1 BW$ for about 10,000 steps (about five miles)" Source: http://www.bbc.com/news/technology-34872563