The AddThis plugin is very unstable. Many times, his performance is very worst.
My platform hosts more than 300 blogs and I check for another solution because I receive too many complaints about his usability.
I'm strained to give a very bad note to the plugin :(
For sure, my last rating was 1 star - BUT !!!
The AddThis team works hard to make a very good plugin and I am not able to not respect that!!
So, my new rating is 4 stars.
Congratualtions AddThis :D