From Nedarim 62a:
רבא רמי כתיב ועבדך ירא את ה' מנעוריו וכתיב (משלי כז, ב) יהללך זר ולא פיך הא באתרא דידעי ליה הא באתרא דלא ידעי ליה
Rava contrasted. It is written (in I Melachim 18:12): 'And [I] your servant [Ovadiah, speaking to Eliyahu] feared God from his youth.' And it is written (in Mishlei 27:2), 'A stranger should praise you and not your own mouth.' [Resolving the contradiction]: Here is where he is known, and here is where he is not known.Nowadays, through the wonders of the Internet, we have another option, of praising oneself through a stranger, where one is not otherwise known.