A TXT (Text) Entry was originally intended for human-readable text. These records are dynamic and can be used for several purposes.
The TXT Value is what the record 'points to', but these records aren't used to direct any traffic. Instead they're used to provide needed information to outside sources.
The First record is used for a SPF, Sender Policy Framework, records, those records are used by many email systems to help identify if email is coming from a trusted source, helping filter out spam or messages pretending to be from your domain (called spoofing). More information on SPF records can be found at http://www.openspf.net/
The second record is used for DomainKeys, which is also used to verify that email came from a trusted source. More information on DomainKeys can be found at http://www.dkim.org/