This text appears to be encoded in base64 and can be decoded back into plain text as follows:

{key = 'decoding a link from 4chan'; text = 'Base64 is an algorithm for encoding binary data such that the resulting string contains only characters in the range of ASCII code 32 through 126, inclusive - i.e., all printable US-ASCII characters except space (space character being represented by equals signs '=') and forward slash (/). The base64 specification does not require padding with zeros to bring each group size up to a multiple of 3 octets. Base64-encoded data is often used as the body of an email when sending binary information via unsecured channels such as IMAP/IMAPS, POP3/POP3S or even in clear text within URI query strings because these protocols have character set restrictions which make it difficult (though not impossible) to send raw binary data. This tool can be used for debugging and testing purposes only; never use this function on user-supplied input without proper sanitization! ';}

Decoding a link from 4chan