Seems effective, but has very sketchy (undisclosed) privacy policy "MyBrowserAddon may disclose personal information to third parties it engages to provide services that involve data processing on its behalf. Also, if some or all of the assets of MyBrowserAddon are sold to a third party, such third party will be entitled to use the personal information disclosed by You, but only under the terms of this privacy statement."

annoying - it opens a popup after installation without the user clicking on anything and without the user requesting to view any page.

According to Panopticlick, this actually made it worse - I was in a bracket where one in 5,000 browsers had my font set, with this extension one in 253,000 browsers had my font set. You can't change the false data it sends either, so you can't fit yourself into a more common font set.