To sign your posts like I did above (on
talk pages, for example) use the '~' symbol. To insert just your name, type ~~~ (3 tildes), or, to insert your name and timestamp, use ~~~~ (4 tildes).
Wikipedia style is that people generally reply to messages left on their own talk on the talk page of the person who left the message for them - that way, people don't have to keep an eye on a whole long list of user talk pages (one for each person whom they are having a "conversation" with).