www.do.com for sharing tasks, projects and files
www.trello.com a productivity tool
www.appointlet.com lets your clients make appointments with you online
www.launchrock.com is a site to create a cool' coming soon' page for your new website, building the anticipation and allowing visitors to register
www.wufoo.com lets you create all sorts of online forms to go on your website
www.mailchimp.com is an oldee, but a goodee, easily design and send out professional email newsletters, allows you a newsletter sign up form for your website too
www.mural.ly  allows you to think, imagine and discuss creative ideas
www.cardflick.com allows you to design your business card to have on your phone and then share it when you need it
www.surveymonkey.com create and send surveys for free