Talk pages can be used to comment on a particular page or its contents, and to leave messages for individual users. Longer discussions should generally take place in the.
Every page has a "discussion" link at the top, just above the page title. This link takes you to a separate page where you can leave a comment concerning that particular page or its contents, e.g. the works contained in a work page. If there are already some comments on the page, the easiest way to add a new topic is by clicking the "+" sign at the top of the talk page. Don't forget to sign your comments (see below).
Every user has his own user page (which may be empty), and his own user talk page. Clicking on a user name anywhere in the wiki will usually take you to the corresponding user page, and clicking on "discussion" on the user page gets you to the user talk page. Use the "+" link at the top of the user talk page to add a new message. The user will be notified of the message the next time he logs on to IMSLP. Note that the message will be visible for everyone.
Users are free to choose whether to reply to messages in their own talk page, or on the talk page of the message author. Replying on the own talk page has the advantage keeping the conversation in one place, but it should be noted that in this case the author of the original message is not notified about the reply, unless a note is left on his talk page, too.
All comments on talk pages should be signed by putting four tildes in a row: ~~~~. This will automatically put your username and the time of your posting. You can also use the second button from the right above the edit window.
Feel free to award users for their contributions at a high level. A list of Barnstar templates can be found here. Please add these to the User page and not the talk page! Also, make sure not to give them out frivolously; they are to award massive contributions of one sort or another, and should not be cheapened.