If the path is easy to get traffic to your site, it is probably not the best one for promoting your web site.
You may have heard of link farms or free-for-all link sites that can show a link back to your site, giving you a way to "increase traffic". Well, many website owners have exactly the same idea! The link to your site will get lost in the crowd of links on the page, will disappear when fresh links appear, you will be susceptible to unwanted emails and many of these farming sites are not favored by search engines and classed as spamming or Spamdexing!
Backlinks (links back from other websites to yours) are extremely valuable! The more "genuine" backlinks means a better ranking amoungst search engines and a genuine increase in your sites popularity. Search engines require ways to confirm page relevancy and a known method is to examine one-way links coming directly from relevant websites.
Traffic exchange means visitors, but more often than not, from sites not specific your site!
You may have been lucky in getting a reliable number of visitors after launching your website, but now everything has tapered off and doesn't look likely to get better in the next period. Maybe you're ignoring the importance of site promotion! Exceptional design is not the be-all and end-all of running a website; you will need a marketing plan and you will need to define your objective.
Mass emails are too random and illegal if unsolicited Unsolicited Electronic Messages Act 2007 and not the way to the top, same with link listings or Spamdexing as mentioned above.
You need to ensure that your website stays visible if you want to remain at the top. To succeed, search engine optimisation (SEO) must be never-ending!

