Edit-- I just confirmed for myself that it does at least in Sparrow Lite http://dl.dropbox.com/u/7400069/sparrow_lite_signature.png
Edit-- I just confirmed for myself that it does at least in Sparrow Lite http://dl.dropbox.com/u/7400069/sparrow_lite_signature.png
If Thunderbird or Mail.app advertised itself on emails you send out by default, people would be up in arms.
Do you see Gmail doing that? No. And even then, these three programs are free.
If I pay for Sparrow (and I did, and it was disappointingly slow and had poor UX -- but it sure did look pretty in the screenshots!), I don't want it to advertise itself to everyone I email -- because I'm not here to do your marketing for you. Let me opt-in to your poorly thought out self-promotion instead of pissing me off.
Down vote away!
I did buy it. It still advertises itself by default.
Side-note: I just re-read my comment and I sounded like a jerk. I would also like to apologize for that. The sarcasm didn't age well (to my ear anyway).