500k users for a startup, begs believe for me.

Techcrunch has a startup listed as having 500k users . This begs believe for me.

http://techcrunch.com/2014/05/06/smore-raises-1-7m-seed-round-for-its-single-page-website-builder/

If the figures are real, how on earth does a startup get those sorts of figures in a market that seems expensive to market to