As their name says, Simplenote is not very versatile. You have a list of notes, which are just plain text (you can get a preview of Markdown formatted text, though), just tags as meta-data.
Simperium, the company behind Simplenote, was founded according to Crunchbase in 2010 by Fred Cheng and acquired by the company behind WordPress, Automattic.
Simplenote started out with a very easy to use iPhone app that synced with their website. Syncing seems to be said to be one of the things that they do really well.
fritzmix 