Interesting, I've never heard the term busker before. Outdoor performances really impress me--it takes guts to perform for an audience that may want nothing to do with you, compared to performing at a theatre where people have paid to see you. And often there's something very unique--I saw a guy playing very intricate music on a platform of partially filled water glasses. I could pick up a flute a play a note, perhaps badly but I could play it...I don't know the first place to begin with getting a glass to make noise like that. Unfortunately I didn't have any cash ):

I'm more discerning about what I tip for online because when I like to make a larger contribution. I feel weird about putting just a few dollars on my debit card, there are always signs in stores about minimum orders. I also spend more time with the online stuff...a podcast could give me weeks of entertainment whereas a street performer can offer an hour or so and I usually only stick around for a few minutes.