1.
right?, don't you think?
A casual, truncated form of でしょう used to seek confirmation or agreement. Common among all speakers but especially associated with feminine speech.
2.
see?, I told you so
Used when the speaker's prediction or opinion turns out to be correct, with a tone of vindication.
Common patterns
でしょ is the casual truncation of でしょう. Rising intonation signals a question seeking agreement (sense 1), while falling intonation conveys "I told you so" (sense 2).
でしょう is the polite/formal version and is used in weather forecasts, polite conversation, and formal speech.
Usage
With rising intonation, でしょ is softer and more conversational than だよね. It's frequently used when showing something to someone and expecting a positive reaction.
Related Words
Related:
だよね (similar confirmation-seeking)