Thanks for the feedback! The reason the Facebook and Google+ buttons are different is that, because of differences in their implementation, ShareMeNot requires users to click twice (once to enable/load the real button, and a second time to click the real button). With the ShareMeNot tweet button replacement (and others), on the other hand, users only need to click once. The difference in text is meant to convey that just clicking the ShareMeNot replacement button won't be sufficient to carry out the action (it will only enable the real button). However, many have requested that we shorten the text -- I'll look into doing so this week.
Thanks!
Franzi