I understand your need to confess and have been in a similar situation with my pdoc about seeing what I though was a "private" online profile. I felt an overwhelming urge to tell him for the longest time and chose not on the advice of people on PC and my T friend. My T friend emphasized I should think about what it would accomplish for me to tell him. I thought it was fair to him but I now understand it had nothing to do with him (and he knew anyway as the site shows who looks at profiles). It was, for me a way I thought I could connect with him on a personal level by talking about it. I'm glad I didn't tell him because that likely wouldn't have happened and he would have probably tried to minimize it as much as possible.

So I'm just wondering if there is another reason behind your urge to confess- like a way to connect with him? If that's it I wouldn't say anything. You didn't do anything wrong, the profile is public. Even though he uses an alias, he's disclosed personal information that made it easy fr you to figure out. My take on the googling and Facebook snooping is that Ts are more aware of their online presence. If they choose to create profiles they are aware clients will see them and don't think much of it. Or If you want to see if he'll get angry about it (which he shouldn't) to shake up the dynamic of your relationship then I might go ahead and tell him.