There is a trademark http://tess2.uspto.gov/bin/showfield?f=doc&state=s6p9qa.3.3 for "Stickies"
that pre-existed your registration. If you clashed with their mark and they successfully sued you, you could end up picking up a % of their legal costs. "Stickies" is also an Apple Mac application according to Wikipedia and that would probably be protected by existing use status. All in all the domain has little value, apart from the potential to get you into trouble.