TLS aims to provide data integrity and privacy between two trusted parties. Information exchanged over the latest version of TLS should be secure from being exposed to third parties in unencrypted form. Additionally, third parties should be unable to modify that information: this is the concept of data integrity, and is the reason an integrity check is performed on each message.
However, even though application data transmitted over a properly-established TLS connection is secure, some metadata and connection information is necessarily exposed to third parties. Without additional obfuscation outside of the scope of SSL/TLS, an observer will be able to discover:
In addition to the data listed above, additional information may be inferred based on the timing of network requests. Outdated SSL/TLS versions have additional identified vulnerabilities, and in the future one must anticipate the TLS spec will be versioned to ameliorate any vulnerabilities identified in the future.