Backlink pinging?

I'm rather new to backlinking and link building but I've recently found some sites which contain do-follow links in comments and/or profile pages. Is it necessary to ping these websites?

Lets say I create a profile on website1.com, and on that profile I put a link to my main website. Am I supposed to ping website1.com/myprofile?

Also what would be the best tool to do this?

Thanks.